Thank you for reaching back out to us, bookkeeping23. You have done the first half by recording the refund for the customer's overpayment, such as creating the expense, using the A/R account, and adding the amount correctly! The next step would be to link the refund to the customer's credit or overpayment. Here's how:

1. Select the + New icon.
2. Click Receive payment or Receive invoice payment.
3. Locate and select the same customer you used for the expense.
4. Fill out the required fields.
5. Select the checkbox for the Expense you created under the Outstanding Transaction section.
6. Click Save and close once completed.

Please let me know if you need additional help once doing this. For future reference, you may check out this article: Apply a credit memo, credit, or refund to a customer. The Community and I are here to assist. Have a lovely day!