Broken parts, promises and still no fix.

I bought a vehicle at Citton Cars Menlyn. After 1 day I noticed some water in the rear brake light. I took it back and they exchanged it with another car's rear breaklight. Nice, no worries. Then a few days later, my wife was driving with me in the car and when she turned the volume knob on the radio, it was malfunctioning. I informed the car dealer (Graeme Howel) that I had to send a video clip for proof. Two days later, I had to phone him to ask what was happening. He rep**** that they were busy with an Insurance claim on the radio. They should inform the customer I would think!! Another day after that, I had to phone again. The car dealer then informed me that they are willing to replace the radio with an aftermarket one, and the total price is 7k and I had to pay 2k of that!!! I asked him why, and he rep**** that the radio was working when they tested it.........so I broke it? I was using the steering wheel controls and did not know the volume knob was broken. I then asked him if they were willing to pay the 5k for a radio if I found one. I was then informed that the radio PLUS installation was 7k. I then informed him that I was willing to replace the radio if they were to buy it. I am still waiting for an answer from Thursday last week. It's now Monday. So in all, they are willing to "fix" the problem if you pay 1/4 of the price. And they only fix 50% of the faults.