Overpayment letter from the unemployment office - 16 weeks in

The agency says I reported earnings incorrectly, but I think I followed the instructions. I do not usually post, so bear with me. 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 4 months ago, and it settled down once I kept a simple log of every call and form.