Our Overpayment Notification Letter Template addresses overpayment errors promptly, ensuring clear communication and resolution for all parties involved. The salary overpayment resulted because .The new model letters include a letter asking an ex-employee to pay back an overpayment discovered after the individual left the organisation. (1st Reminder Letter to Employee who leaves before Recovery Complete). Dear. Model policy for the overpayment and underpayment of pay. 10 Standard Employee Letter Templates.