Told I owe money back on my benefits - 4 months and counting

After 3 weeks of benefits I got a notice saying I must repay some of it. I did not notice any errors at the time. Has anyone disputed one of these?

If you are unsure, free legal aid in your area may help for this kind of notice.

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.