fix(payments): ensure ObjectId casting for duplicate check query

components/payments/paymentService.js

@@ -582,19 +582,27 @@ const checkDuplicatePayment = async (query = {}) => {
   }
 
   const filter = {
-    user: userId,
     isDeleted: { $ne: true }
   };
 
-  const targetClasses = [];
+  if (mongoose.isValidObjectId(userId)) {
-  if (classId) targetClasses.push(classId);
+    filter.user = new mongoose.Types.ObjectId(String(userId));
-  if (classes) {
+  } else {
-    if (Array.isArray(classes)) targetClasses.push(...classes);
+    filter.user = userId;
-    else targetClasses.push(...String(classes).split(',').map((s) => s.trim()).filter(Boolean));
   }
 
-  if (targetClasses.length) {
+  const rawClasses = [];
-    filter.classes = { $in: targetClasses };
+  if (classId) rawClasses.push(classId);
+  if (classes) {
+    if (Array.isArray(classes)) rawClasses.push(...classes);
+    else rawClasses.push(...String(classes).split(',').map((s) => s.trim()).filter(Boolean));
+  }
+
+  if (rawClasses.length) {
+    const classObjectIds = rawClasses.map((id) => {
+      return mongoose.isValidObjectId(id) ? new mongoose.Types.ObjectId(String(id)) : id;
+    });
+    filter.classes = { $in: classObjectIds };
   }
 
   const payments = await Payment.find(filter)