Told I owe money back on my benefits - any advice?

After 4 weeks of benefits I got a notice saying I must repay some of it. It has been a long 4 weeks. I cannot afford to repay it all at once. Has anyone disputed one of these?

Collect your pay stubs and certification records for the weeks they name. Mine showed the error was a date mix-up.

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