Got an overpayment notice, what now?, production planner here

I received a letter saying I was overpaid about $1100 on my claim. I worked as a production planner before this. I cannot afford to repay it all at once. 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.