Overpayment letter from the unemployment office - 7 weeks in

The agency says I reported earnings incorrectly, but I think I followed the instructions. I do not usually post, so bear with me. I did not notice any errors at the time. 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.

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.