Overpayment letter from the unemployment office - 9 months and counting

I received a letter saying I was overpaid about $800 on my claim. 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 9 months ago, and it settled down once I kept a simple log of every call and form.

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.