This brief but important letter notifies a customer that he or she has overpaid you. It can serve as a very good customer relations letter.You have to tell your credit or debit card company about any error you're disputing within 60 days of when the first statement with the charge was sent to you. The salary overpayment resulted because . You receive a threatening letter that demands payment on a debt you've never heard of. We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error. The purpose of this section is to make the most current forms available with a single resource. Forms are used to collect information.