Bad service and still waiting for repaired vehicle

My A180 was taken for a service in centurion. During the service the brake pads were changed and the tires were changed. After the service I took my car home but I wasn't happy with it coz the brakes were making noise but the told me that it's because the brake pads are new but later I had a puncher which was due to the fact that they replace run flats with normal tyres. I work in the NC, so I called Kimberly to collect the car for weeks ago and I'm still waiting for my car. Gariep motors came to collect the car and they told me that the brake caliper was loose and the fixed it. But after that they were suppose to replace my tires with run flats but I struggled because them and centurion didn't come to an agreement but once I told them I need my car, the managed to sort it out and I had to pay the difference. Since I made the payment I haven't received my car and I'm going for the second week. My car has been with gariep motors for almost 4 weeks due to tires and the brake caliper. I don't have another car and every times when I called them they say the will come back to me and they never do. I'm even considering selling the car and buying another. Mercedes Benz disappointed me.