Let me provide how QuickBooks Payments works, @HalimiB.
Once customer pays via QuickBooks Payments, the invoice created in QuickBooks Online (QBO) will automatically be marked as paid. The payment will be posted in the Undeposited Funds account.
You can visit this reference to learn more about the instructions: Receive and process payments in QuickBooks Desktop.
I'm including these articles to help guide you more about the QuickBooks Payments as well as their standard pricing:
For future reference, read through this article to learn more about how to reconcile your account match your bank and credit card records to have accurate financial data.
Feel free to get back to me if you have any other payment concerns. I'd be glad to provide you additional assistance.