Got an overpayment notice, what now? - 9 months and counting

After 19 weeks of benefits I got a notice saying I must repay some of it. I am in Cleveland, in case local advice matters. 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 last year, and it got easier once I kept a simple log of every call and form.