TYREMART TOKAI RIPP OFF!!!

Went to have a back box exhaust fitted, was told I need a complete system from front to back. I had it done. Had to go back a second time coz the exhaust was blowing and I was using so much fuel. Took my car to another exhaust fitment centre because I couldn't understand why the exhaust was rattling, they told me that they can't understand why there wasn't a knucke joint on my car because all front wheel drives have that on and I need to take my car back. I then went for a second opinion and took my car where I usually take it without saying what the previous place told me and he asked me why wasn't my knuckle joint put back. I went back to Tyremart this morning and all they could tell me is that its not needed and that I didn't have one on before! They also showed me in their book what the complete exhaust system looks like for my car which also had some swivel thing on, but my exhaust don't have it! So how can they possibly charge me for a complete exhaust from front to back but just choose not to add it. After all my car is a front wheel drive and that is needed. Total RIPP OFF!!!!! I wish I just allowed them to replace the back box, then my car part would still be there