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.How long will it take to get a decision? Most customers are receiving responses less than two weeks after completing and submitting the DocuSign. A business may request a refund due to overpayment of tax. The overpayment may be the result of an amended return, audit or more money paid than was owed. The salary overpayment resulted because . We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error. DOB NOW filing fee screen. We inform people about the fact and amount of the overpayment, their right to appeal, and the options to repay or, in some cases, receive waivers for the debt.