If you were overpaid, you will receive a written notice in the mail. Do not call 800-533-6600 to dispute your overpayment.You will need to appeal the determination as described below. No state pursues unemployment overpayment cases as zealously as New York. Although there are broad requirements under federal law regarding UI benefits and financing, the specifics are set out under each state's laws. This chapter deals with state law provisions for identifying, establishing, and collecting Unemployment. Insurance (UI) benefit overpayments. Overpayment: When a state agency finds it has paid a worker UI benefits the worker was not entitled to.