Shock at being scammed

I had my car in for repairs through an Outsurance claim at Domestic Spray and Repair. Repairs on my car were completed, as I was about to leave Domestic Spray and Repair, I noticed my petrol cap wasnt closed and it wouldnt close. Domestic Spray contacted Outsurance to ask them if they would let a diagnostic company check if the issue was related to my claim. Domestic Spray and Repair outsourced this to Motolek. Motolek provided a report that my Accuator needed replacing. Domestic told me what it would cost and there would be a labour charge. I decided to order the product myself and asked a friend to install it. My friend figured out that the Accuator part was not needed and it was a very simple fix which he did by himself. I am now short R927.71 which Hyundai will not reimburse. So what if I had booked my car in, I can assume that I would've had to pay for a part that was never needed plus a labour charge. Never being wiser that I was scammed. Can assume because I'm female I dont know anything about cars (which I dont) but I at least never booked it in. I've appealed to Motolek, Domestic Spray and Repair and Outsurance for assistance to resolve this and no one has taken any responsibility or assistance in this matter. Motolek continue to ignore me. I'm shocked that they can take advantage and dont even bother replying.