Hey there, MerryK. 

Thanks for dropping by the Community this morning, I'm more than happy to help. If you want to refund your customer for the overpayment, you can follow these steps:

Step 1: Record the refund for your customer:

1. Select  the + New button.
2. Click Expense, Add expense or Check. Also, It's important that you're in  Accountant view when you complete these steps.
3. Select the customer you want to refund from the Payee ▼ drop-down.
4. From the Payment account ▼ click drop-down, select the bank account where the overpayment was deposited too.
5. On the first line of the Category column, select an Accounts Receivable.
6. Enter how much you want to refund in the Amount field.
7. Fill out the rest of the field as desired, then select Save and close.

Step 2: Link the refund to the customer's credit or overpayment:

1. Select + New again.
2. Click Receive payment or Receive invoice payment.
3. Select the same customer you used for the check or expense.
4. Fill out the other fields as desired.
5. Under the Outstanding Transaction section, click the checkbox for the Expense or Check that you created.
6. Make sure the payment is equal to the open balance, then select Save and close.

And that's it. I'm providing a link below to the steps shown above as-well-as a tutorial video on the entire process. 

• Record a customer refund or Overpayment.

If you have any other questions or concerns, or need further assistance, please don't hesitate to reach out here. Thanks again and have a lovely day.