Got an overpayment notice, what now? after 18 years as a customer-service rep

After 23 weeks of benefits I got a notice saying I must repay some of it. There are 18 people counting on me, so I am trying to be careful. The letter mentions an appeal window and a repayment plan. Are payment plans possible?

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.