There may be situations when an order needs to be cancelled by a customer but you have taken a prepayment that needs to be refunded in cash rather than credit. Here's how to do this.
First of all, DO NOT create an invoice.
1) Open the customer in C/V central and check the vendor checkbox (this is needed so you can write a check).
2) Navigate to Bank → Payments → Create New.
3) On the lines, use Customer Prepayment as the account. Fill out the rest of the fields normally and Save.
4) Navigate to Sales → Cash Receipts → Create New.
5) Enter the Customer name.
6) In the Invoices section, check the Payment entry.
7) Click on Credits tab and check the Prepayment entry.
8) Click Save and Close.
9) Verify in Customer / Vendor central that there are no balances on the documents.