How to report a business for paying below NMW England?
I've been applying for jobs and jobs for the past year and finally got a role at some restaurant. The first day, they made me work 13 hours with 1 break after 9 hours, which lasted around 5 mins, and then another break about an hour later that lasted like 20 mins max. They're also paying me less than NMW for my age bracket, paying me ~£5.40 per hour when I should be receiving £10.85. It's £70 for the entire day (13 hours). I quit after the first day because the workload was too much as they made me wash over 200 dishes, and it was not worth it for the pay and for that pay my health wasnt worth it (I still struggle if I made the right decision as I am still looking for a job). They also made me wait for half n hour in the cold outside the shop because they were late themselves, and I was forced to seek refuge in some shop for warmth. They do it in cash payments and there's no record of them paying me as my pay will come this Sunday either through cash or bank transfer so I'm just wondering how can I report this business as they are preying on desperate students like myself and others and I cannot let them get away with this. England and worked there for 1 day.
TLDR: Employer underpaying below NMW and didn't offer adequate breaks. Looking to how to report them.