repairs not done

I book my cell phone for repairs on job no ***6 at east London. I went to go fetch my phone a sony z3 today. when I inspected it I noticed that the inside of the camera is full of dust and dirty and not cleaned. this was one of the reasons of I booked it in as this is a sealed waterproof unit dust is not supposed to go in there. this just means that the technician did not do his job as he didn't even clean this also the person who inspected his work did not do his work. how do I know that the other faults was even repaired if a basic thing like wiping a lens was not done? I don't think I will renewing my line with a company that cant be bothered to wipe a lens. I now have to wait another week for a lens to be whipped at the advance repair centre and spend another R200 on petrol to go fetch my phone in east London.