Overpayment letter from the unemployment office - 12 months and counting

The agency says I reported earnings incorrectly, but I think I followed the instructions. 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 12 months ago, and it settled down once I kept a simple log of every call and form.

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