If your customer overpays you, you can post a refund.

1. Go to Bank accounts and select the bank to refund from.
2. Click Customer refund.
3. On the Customer Refund window, select the customer in the Account field.
4. Enter the correct Date and any references.
5. Enter the value of the refund in the Refund column against the outstanding Payment on Account (SA).
6. Click Save.