Got an overpayment notice, what now? (Cincinnati)

After 24 weeks of benefits I got a notice saying I must repay some of it. I worked as a bookkeeper before this. The letter mentions an appeal window and a repayment plan.

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

Keep everything in writing and save the confirmation numbers. It saved me later.