diff --git a/src/application/payment/payment.service.ts b/src/application/payment/payment.service.ts
index 97c38a8..59f41b8 100644
--- a/src/application/payment/payment.service.ts
+++ b/src/application/payment/payment.service.ts
@@ -61,7 +61,7 @@ export class PaymentService {
         await this.purchaseDataAccess.createPurchase(payment.userId.toString(), payment.courseId.toString(), payment._id.toString());
 
         payment.paymentStatus = PaymentStatus.Completed;
-        await this.paymentDataAccess.updatePaymentStatus(payment._id, PaymentStatus.Completed);
+        await this.paymentDataAccess.updatePaymentStatus(payment._id.toString(), PaymentStatus.Completed);
 
         const registerCourse = await this.userDataAccess.registerCourse(payment.userId, payment.courseId);
         if (!registerCourse.success) {
@@ -78,7 +78,7 @@ export class PaymentService {
 
         await session.commitTransaction();
         await session.endSession();
-        
+
         return { success: true, payment: payment }
       }