Terrible service!

I went to fit an aftermarket exhaust to my Audi TTRS at Power Pipes in Johannesburg. I was quoted R18 000.00 for a new system. They said they had done many Audi TTRS’s. After many attempts to build an exhaust, they had failed. They told me there is something wrong with my car and that is why they can't get it right and I was not compensated in any way. I was told by a friend of mine to use his son who had split from his father. The son said he could rectify the problem and it would not cost more than R10 000.00. After completion he presented me with a bill of R28 000.00. The sound was no better than before. I do not use my car often and every time I did the battery was completely dead. Only then did I realise that they had connected an electronic valve directly to the battery. Reluctantly he said I must bring the vehicle to Kyalami which is 120Km from me. I said I would take it to an auto electrician near me and he could pay the account, he refused that. It is a long story to say both the father and the son take your money without doing the job. I would be very careful about using either of them.