Did my first shift with them and i was underpaid. ...

Did my first shift with them and i was underpaid. Contacted the support team multiple times to tell them the correct hours I did, and was simply told the employer confirmed that my working time was correct and that was that. When I stated that they send me a copy of the paper time sheet that I used on the shift, they could not provide it and completely ignored me. You could also see on the app the time and the location I was when I arrived and left the venue that evening. Disgusting.
Glad I did one shift to test it first, much better agencies out there that give you signed paper copy of your shifted hours to avoid mistakes like these. I then ask for my p45 and to be remove from the system and it took them weeks to do so. Absolutely ridiculous.