Got an overpayment notice, what now? (update)

After 20 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?

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.

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.