SHOCKED OVER SHOCKS

I have used Supa Quick Hillcrest for a number of years to change tires and have never had a problem, however around 4 weeks ago I went there to have my car’s shocks replaced and ended up paying around R10,000 for shocks which were installed incorrectly, with missing parts. Long story short, after collecting my car and driving plus minus 5km, i noticed there was a shudder at the left front wheel and also a warning engine light came on I immediately suspected the fault had nothing to do with the work recently done by Supa Quick and drove straight to Mercedes to have them attend to the engine. After checking the car Mercedes phoned me and asked who replaced the shocks so I said supa Quick Hillcrest and they were horrified as the workmanship was disgusting and the job was actually incomplete in that they had not replaced an integral part of the shocks! This they explained to me would of caused the vibration of the wheels and intern the warning light to come on, they also explained that the shocks come complete with the part that was missing and that they could not buy that particular part separately, therefore I would have to replace the complete shock again, they then told me to take the other shocks back to Supa Quick as they would be no use to me or anyone else other than Supa Quick, then I said please can you actually put this in writing and take a photo of the shocks. They took photos of the shocks showing that an entire part of the shocks were missing and wrote a letter stating how poorly the shocks were installed. Once I had replaced the shocks again COSTING ME ANOTHER R9,000. I then contacted supa Quick and reported the problem and advised them that I would return the shocks to them with a report from Mercedes I also asked them to credit me for the supply of the inferior shocks they had installed, the labour I was prepared to pay for. Supa Quick was not interested in my complaint and instead INSISTED I WAS AT FAULT AND TO BLAME for something they did incorrectly. They refuse to give me my money back and refuse to admit when wrong. Shocking customer service and I WILL NEVER RECOMMEND THEM TO ANYONE. All I asked was for some customer service and for some help in any way. Extremely disappointed and busy taking it further.