Told I owe money back on my benefits after 4 years as a marketing coordinator

The agency says I reported earnings incorrectly, but I think I followed the instructions. I am in Knoxville, in case local advice matters. I did not notice any errors at the time. Has anyone disputed one of these?

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.