Got an overpayment notice, what now? after 10 years as an event coordinator

After 6 weeks of benefits I got a notice saying I must repay some of it. The letter mentions an appeal window and a repayment plan. Has anyone disputed one of these?

I asked for a waiver and a plan in the same call, and they gave me both forms. It was less scary than I expected.

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