Reporting part-time earnings while on benefits

My hours change every week at my new part-time job and I am afraid of reporting wrongly. Sometimes my paycheck is late by a week. Who can I ask without risking my claim?

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.

The claimant handbook has worked examples for part-time pay. Mine was clearer than the phone line.