diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp
index 5c3327a..d08d957 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp
@@ -323,7 +323,7 @@ void InventoryManagementService::sendNotification(User* user, const std::string&
 				Factory::getObject<Notification>(
 					user->getId(),
 					user,
-					"InventoryManagementService: " + title,
+					title,
 					message,
 					util::Timestamp()
 				);
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp
index ba3282a..80e167d 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp
@@ -86,7 +86,7 @@ void PaymentManagementService::sendNotification(User* user, const std::string& t
 				Factory::getObject<Notification>(
 					user->getId(),
 					user,
-					"PaymentManagementService: " + title,
+					title,
 					message,
 					util::Timestamp()
 				);
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.cpp
index 799d701..45c6fe4 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.cpp
@@ -175,7 +175,7 @@ void ServiceManagementService::sendNotification(User* user, const std::string& t
 				Factory::getObject<Notification>(
 					user->getId(),
 					user,
-					"ServiceManagementService: " + title,
+					title,
 					message,
 					util::Timestamp()
 				);
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.cpp
index 613a3d2..39f9148 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.cpp
@@ -111,9 +111,23 @@ void UserManagementService::updateUserDetails(const std::string& userID, const s
 	int index = usersMap.find(userID);
 	if (index == -1)
 	{
-		throw std::runtime_error("User does not exist!");
+		throw std::runtime_error("User does not exist!\n");
 	}
 	User* user = usersMap.getValueAt(index);
+	if (email != user->getEmail())
+	{
+		if (util::isEmailDuplicate(email, usersMap))
+		{
+			throw std::runtime_error("Email already exists!\n");
+		}
+	}
+	if (phone != user->getPhone())
+	{
+		if (util::isPhoneDuplicate(phone, usersMap))
+		{
+			throw std::runtime_error("Phone number already exists!\n");
+		}
+	}
 	user->setEmail(email);
 	user->setPhone(phone);
 }
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Validator.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Validator.cpp
index cdba432..f56d660 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Validator.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Validator.cpp
@@ -108,6 +108,17 @@ bool util::isPasswordValid(const std::string& password)
     return hasUpper && hasLower && hasDigit && hasSpecial;
 }
 
+/*
+ * Function: isUsernameDuplicate
+ * Description: Checks if the given username already exists among active users.
+ * Parameters:
+ *     username - string containing the username to validate
+ *     usersMap - map of user objects keyed by identifier
+ * Returns:
+ *     bool - true if the username is already in use by an active user, false otherwise
+ * Notes:
+ *     - Only considers users with state util::State::ACTIVE
+ */
 bool util::isUsernameDuplicate(const std::string& username, const util::Map<std::string, User*>& usersMap)
 {
     int index = usersMap.findIf(
@@ -119,6 +130,17 @@ bool util::isUsernameDuplicate(const std::string& username, const util::Map<std:
     return index != -1;
 }
 
+/*
+ * Function: isPhoneDuplicate
+ * Description: Checks if the given phone number already exists among active users.
+ * Parameters:
+ *     phone - string containing the phone number to validate
+ *     usersMap - map of user objects keyed by identifier
+ * Returns:
+ *     bool - true if the phone number is already in use by an active user, false otherwise
+ * Notes:
+ *     - Only considers users with state util::State::ACTIVE
+ */
 bool util::isPhoneDuplicate(const std::string& phone, const util::Map<std::string, User*>& usersMap)
 {
     int index = usersMap.findIf(
@@ -130,6 +152,17 @@ bool util::isPhoneDuplicate(const std::string& phone, const util::Map<std::strin
     return index != -1;
 }
 
+/*
+ * Function: isEmailDuplicate
+ * Description: Checks if the given email address already exists among active users.
+ * Parameters:
+ *     email - string containing the email address to validate
+ *     usersMap - map of user objects keyed by identifier
+ * Returns:
+ *     bool - true if the email address is already in use by an active user, false otherwise
+ * Notes:
+ *     - Only considers users with state util::State::ACTIVE
+ */
 bool util::isEmailDuplicate(const std::string& email, const util::Map<std::string, User*>& usersMap)
 {
     int index = usersMap.findIf(
@@ -139,4 +172,4 @@ bool util::isEmailDuplicate(const std::string& email, const util::Map<std::strin
         }
     );
     return index != -1;
-}
+}
\ No newline at end of file
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.cpp
index 74500e8..660decf 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.cpp
@@ -158,10 +158,33 @@ void AdminMenu::viewStockLevels()
 {
     util::clear();
 	auto inventoryItems = m_controller.getInventoryItems();
+	bool hasActiveItems = false;
+	std::cout << "View Stock Levels" << std::endl;
+	if (inventoryItems.isEmpty())
+	{
+		std::cout << "No items found in Inventory.\n";
+		util::pressEnter();
+		return;
+	}
+	for (int index = 0; index < inventoryItems.getSize(); index++)
+	{
+		const InventoryItem* item = inventoryItems.getValueAt(index);
+		if (item->getState() == util::State::ACTIVE)
+		{
+			hasActiveItems = true;
+			break;
+		}
+	}
+	if (!hasActiveItems)
+	{
+		std::cout << "No active Inventory Item found.\n";
+		util::pressEnter();
+		return;
+	}
 	std::cout << std::left << std::setw(15) << "Item ID"
 		<< std::setw(25) << "Part Name"
-		<< std::setw(10) << "Quantity"
-		<< std::setw(10) << "Price"
+		<< std::setw(15) << "Quantity"
+		<< std::setw(15) << "Price"
 		<< std::endl;
 	for (int iterator = 0; iterator < inventoryItems.getSize(); ++iterator)
 	{
@@ -172,12 +195,14 @@ void AdminMenu::viewStockLevels()
 			{
 				std::cout << std::left << std::setw(15) << item->getId()
 					<< std::setw(25) << item->getPartName()
-					<< std::setw(10) << item->getQuantity()
-					<< std::setw(10) << item->getPrice()
+					<< std::setw(15) << item->getQuantity()
+					<< std::setw(15) << item->getPrice()
 					<< std::endl;
 			}
 		}
 	}
+	std::cout << "\n";
+	util::pressEnter();
 }
 
 /*
@@ -273,8 +298,10 @@ void AdminMenu::checkStockAvailability()
 {
 	util::clear();
 	std::string itemId;
-	std::cout << "Enter the Item Id : ";
+	std::cout << "Check Stock Availability \n";
+	std::cout << "Enter the Item ID : ";
 	util::read(itemId);
+	util::clear();
 	const InventoryItem* selectedItem = m_controller.getInventoryItem(itemId);
 	if (selectedItem != nullptr)
 	{
@@ -287,6 +314,10 @@ void AdminMenu::checkStockAvailability()
 			std::cout << "Quantity     : " << selectedItem->getQuantity() << "\n";
 		}
 	}
+	else
+	{
+		std::cout << "Item not Found" << std::endl;
+	}
 	util::pressEnter();
 }
 
@@ -443,6 +474,7 @@ void AdminMenu::removeUser()
 	auto listOfUsers = m_controller.getUsers();
 	auto listOfActiveUsers = filterActiveUsers(listOfUsers);
 	int activeUserCount = listOfActiveUsers.getSize();
+	std::cout << "Remove User \n";
 	if (activeUserCount < 1)
 	{
 		std::cout << "No Active users." << std::endl;
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp
index 2f3a0f9..d354a3c 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp
@@ -144,11 +144,12 @@ void CustomerMenu::updateDetails()
 {
 	std::string email, phone;
 	util::clear();
+    std::cout << "Update Details\n";
 	std::cout << "Enter new email: ";
 	util::read(email);
 	if (!util::isEmailValid(email))
 	{
-		std::cout << "Error: Email is invalid!";
+		std::cout << "Error: Email is invalid!\n";
 		util::pressEnter();
 		return;
 	}
@@ -156,12 +157,12 @@ void CustomerMenu::updateDetails()
 	util::read(phone);
 	if (!util::isPhoneNumberValid(phone))
 	{
-		std::cout << "Error: Phone number is invalid!";
+		std::cout << "Error: Phone number is invalid!\n";
 		util::pressEnter();
 		return;
 	}
 	m_controller.updateUserDetails(email, phone);
-	std::cout << "Profile details updated successfully";
+	std::cout << "Profile details updated successfully\n";
 	util::pressEnter();
 }
 
@@ -260,16 +261,17 @@ void CustomerMenu::viewServiceHistory()
 	const User* currentUser = m_controller.getAuthenticatedUser();
 	std::string currentUserID = currentUser->getId();
 	util::Map<std::string, const ServiceBooking*> serviceBookingsByCurrentUser = m_controller.getServiceBookingsByUser(currentUserID);
+    std::cout << "View Service History" << std::endl;
     if (serviceBookingsByCurrentUser.getSize() != 0)
     {
         std::cout << std::left
-            << std::setw(12) << "Booking ID"
+            << std::setw(15) << "Booking ID"
             << std::setw(20) << "Technician"
-            << std::setw(15) << "Vehicle Brand"
-            << std::setw(15) << "Vehicle Number"
-            << std::setw(15) << "Vehicle Model"
-            << std::setw(10) << "Discount %"
-            << std::setw(12) << "Status"
+            << std::setw(20) << "Vehicle Brand"
+            << std::setw(20) << "Vehicle Number"
+            << std::setw(20) << "Vehicle Model"
+            << std::setw(20) << "Discount %"
+            << std::setw(20) << "Status"
             << std::endl;
         for (int iterator = 0; iterator < serviceBookingsByCurrentUser.getSize(); iterator++)
         {
@@ -278,13 +280,13 @@ void CustomerMenu::viewServiceHistory()
                 ? "Not Assigned"
                 : currentBooking->getAssignedTechnician()->getName();
             std::cout << std::left
-                << std::setw(12) << currentBooking->getId()
+                << std::setw(15) << currentBooking->getId()
                 << std::setw(20) << technicianName
-                << std::setw(15) << currentBooking->getVehicleBrand()
-                << std::setw(15) << currentBooking->getVehicleNumber()
-                << std::setw(15) << currentBooking->getVehicleModel()
-                << std::setw(10) << currentBooking->getDiscountPercentage()
-                << std::setw(12) << util::getServiceJobStatusString(currentBooking->getStatus())
+                << std::setw(20) << currentBooking->getVehicleBrand()
+                << std::setw(20) << currentBooking->getVehicleNumber()
+                << std::setw(20) << currentBooking->getVehicleModel()
+                << std::setw(20) << currentBooking->getDiscountPercentage()
+                << std::setw(20) << util::getServiceJobStatusString(currentBooking->getStatus())
                 << std::endl;
             hasServiceHistory = true;
         }
@@ -308,11 +310,35 @@ Returns:
 void CustomerMenu::completePayments()
 {
 	util::clear();
+    std::cout << "Complete Payments\n";
 	util::Map<std::string, const Invoice*> currentInvoices = m_controller.getInvoicesByUser();
+    if (currentInvoices.isEmpty())
+    {
+        std::cout << "No pending invoices available for payment.\n";
+        util::pressEnter();
+        return;
+    }
+    bool hasPending = false;
+    for (int index = 0; index < currentInvoices.getSize(); ++index)
+    {
+        const Invoice* invoice = currentInvoices.getValueAt(index);
+        if (invoice && invoice->getStatus() == util::PaymentStatus::PENDING)
+        {
+            hasPending = true;
+            break;
+        }
+    }
+    if (!hasPending)
+    {
+        std::cout << "No pending invoices available for payment.\n";
+        util::pressEnter();
+        return;
+    }
 	std::string selectedID = selectInvoiceFromUserForPayment(currentInvoices);
     if (selectedID == "")
     {
         std::cout << "Payment failed.\n";
+        util::pressEnter();
         return;
     }
     util::PaymentMode paymentMode = selectPaymentMode();
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/MenuHelper.h b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/MenuHelper.h
index 09c4ecc..462391b 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/MenuHelper.h
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/MenuHelper.h
@@ -309,6 +309,7 @@ Returns:
 */
 inline std::string selectInvoiceFromUserForPayment(const util::Map<std::string, const Invoice*>& currentInvoices)
 {
+    util::clear();
 	int currentIndex = 1, choice;
 	util::Map<int, const Invoice*> pendingInvoicesForPayment;
 	std::cout << std::left
@@ -316,8 +317,8 @@ inline std::string selectInvoiceFromUserForPayment(const util::Map<std::string,
 		<< std::setw(12) << "BookingID"
 		<< std::setw(15) << "VehicleBrand"
 		<< std::setw(15) << "VehicleNumber"
-		<< std::setw(12) << "TechID"
-		<< std::setw(20) << "TechnicianName"
+		<< std::setw(12) << "Technician ID"
+		<< std::setw(20) << "Technician Name"
 		<< std::setw(10) << "Discount(%)"
 		<< std::setw(12) << "TotalAmount"
 		<< std::setw(20) << "InvoiceDate"
@@ -528,11 +529,6 @@ Return type: const Notification* - pointer to the selected notification
 */
 inline const Notification* selectNotification(const util::Vector<const Notification*>& notifications)
 {
-    if (notifications.getSize() == 0)
-    {
-        std::cout << "No notifications available." << std::endl;
-        return nullptr;
-    }
     util::Map<int, const Notification*> indexedNotifications;
     std::cout << std::left
         << std::setw(6) << "Index"
@@ -549,7 +545,7 @@ inline const Notification* selectNotification(const util::Vector<const Notificat
             std::cout << std::left
                 << std::setw(6) << currentIndex
                 << std::setw(15) << currentNotification->getId()
-                << std::setw(30) << currentNotification->getTitle()
+                << std::setw(35) << currentNotification->getTitle()
                 << std::setw(25) << currentNotification->getCreatedAt().toString()
                 << std::endl;
             indexedNotifications.insert(currentIndex, currentNotification);
@@ -602,6 +598,13 @@ inline void viewAndDeleteNotification(Controller& controller)
 {
     util::clear();
     auto notifications = controller.getNotifications();
+    std::cout << "View and Delete Notification" << std::endl;
+    if (notifications.getSize() == 0)
+    {
+        std::cout << "No notifications available." << std::endl;
+        util::pressEnter();
+        return;
+    }
     const Notification* selectedNotification = selectNotification(notifications);
     if (!selectedNotification)
     {
@@ -675,7 +678,7 @@ inline util::Map<std::string, const User*> filterActiveUsers(const util::Map<std
     for (int index = 0; index < inventorySize; index++)
     {
         const User* user = listOfUsers.getValueAt(index);
-        if (user != nullptr && user->getState() != util::State::INACTIVE)
+        if (user != nullptr && user->getState() != util::State::INACTIVE && user->getUserType() != util::UserType::ADMIN)
         {
             activeUsers.insert(user->getId(), user);
         }