RIP-Off Maintenance plan , Poor Quality Products and Bad Service

I bought a brand new W205 C220 Bluetec 2015 model and few months later the sunroof started malfunctioning and I took it to two different Mercedes dealerships (Centurion and Sandton) but they both failed to get it fixed and they just didn't do anything about it. Again, few months later the USB ports stopped working and when I took it to the dealership to get it checked I was then told that the damage was caused by my negligence, I mean, I've never damaged a USB port from the first I started using a USB, in all the cars I've driven, laptops I used, everywhere else but just theirs. I then bought a new USB unit. In less than three months, that very new USB unit stopped working as well, then took it there, i was told then again that it was my negligence yet again. Yesterday, I booked in my cause the L/F wheel was touching the body of the car when driving and I was told that the shock is bent then I'm told that it's because I've hit a pothole. How can I hit a pothole and not damage a tyre or a rim? This Mercedes Benz warranty thing is a rip-off. They couldn't fix their own factory-faulty sunroof, their USB ports are of poor quality and everything is always customers negligence when they suppose to pay and account. Where do they get the ***** to tell their customers that they've hit a pothole as if they were in the car when the car hit that pothole? ****py car and ****py service!!