Overpayment letter from the unemployment office after 14 years as a security officer

After 6 weeks of benefits I got a notice saying I must repay some of it. There are 14 people counting on me, so I am trying to be careful. I cannot afford to repay it all at once. Has anyone disputed one of these?

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