Overpayment letter from the unemployment office - what worked for you?

After 2 weeks of benefits I got a notice saying I must repay some of it. I did not notice any errors at the time.

Collect your pay stubs and certification records for the weeks they name. Mine showed the error was a date mix-up.

Read the letter for the appeal deadline and act on it, even if you think you will end up repaying. Then ask about a payment plan.