Mercedes Benz - Horrible service continues

A few months back I reported a faulty window switch at Sandowns Motors, which is a Mercedes Benz dealership. I was told that I will have to pay for the damaged switch even if the motor is still under maintenance plan and that it is my fault. I made it clear to the dealership from day one that I disagree with their analysis and feedback. I always take care of my cars and refute the claim that I damaged the faulty switch – I have cars that are older that this car and basically say the part is made of inferior material or related to a factory fault. . The reality is I had way too many issues with this car that I bought brand new and still regret why I did not return it back. I can attach tens of complaint emails I sent in the past to this dealership and the complaints I logged with HelloPeter. Note: even if the car was not covered by maintenance plan, I was still going to expect Mercedes to fix the switch at no cost to me. What pains me is the arrogance, poor service and disrespectful behaviour shown by the dealer's employees and Mercedes Benz SA. I escalated the matter to them (Mercedes Benz SA) more than a month back and I haven't received any feedback from them. This is the first time I have experienced such a horrible service and also been undermined by a Service Provider.