Got an overpayment notice, what now? (update)

After 8 weeks of benefits I got a notice saying I must repay some of it. This is my first time dealing with any of this. I did not notice any errors at the time. 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.

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