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 do I request a refund? A. Fill out the Business Tax Refund Request form to request a refund from the City for an overpayment. To view or print these files you need the free Adobe Acrobat Reader or other PDF reader. The salary overpayment resulted because . Overpayment is recouped in its entirety.