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.MEDI-CAL POTENTIAL OVERPAYMENT REPORTING WORKSHEET - PROPERTY. The salary overpayment resulted because . They can chase you in court and nab a tax return (even nab your money out of the bank). • The provider is willing to complete a letter of agreement for payment. Overpayment in part or full. .34.