Still no pay

Can you believe I've been working at this place for three weeks but the dumb agency HAYS havent even bothered to pay me. Some girl was off and something didnt get processed but that aint my fucking fault, now i'm over my overdraft and getting bank charges, not amused. They said they'll try and pay me by CHAPS today but they can't promise anything, what bollocks. They need to pay me I should be getting 2 weeks pay 2day and if they ever put me on emergency tax they will really hear my mouth!