Suspension Noise problems of the 2008 Nissan Sentra

I have recently had problems with my 2008 Nissan Sentra. Was told my rear tires are cupping and that my tire warranty that I paid extra for is void because it is an issue with the rear suspension of the actual car that is causing the car not to ride properly. I only put 19,000 miles on these new tires. Was told if I replace the tires this will just happen again & again. Nissan inspected the car and said the rear member is not damaged or bent but the car is out of alignment. They also said that these car were built so that the rear is fixed & cannot be aligned only the front can be aligned. Their suggestion is to add shims to the rear to help the car to ride better & be more in alignment and that should help the problem it is creating with the rear tires cupping. When I purchased my car they convinced me to also purchased a rather expensive extended warranty that was said to cover almost everything. Now I am told the warranty does not cover this ( because it is an add on part, not a replacement part) and that I am expected to pay for this. First of all this sounds like a bandaid fix to a problem Nissan should be addressing if this part of the vehicle is faulty. I have not had any damage or accident to the rear of my car that would cause this. It clearly is some sort of defect. Not sure why they would make a car that cannot be aligned in back. Now they are telling me that although it shows no obvious damage, maybe I hit a pothole that caused it to go out of alignment. This is ridiculous! I think they are grasping at straws to make excused for their vehicles defect. Even if I did hit a pothole. . . If the car was built & manufactured properly, a pothole should not throw the entire fixed rear alignment out of wack enough to ruin new tires. If this is how they make cars then I don't plan on buying my next car with Nissan. Sorry Nissan but you just lost a good customer!.

Since the day I purchased the vehicle I have had ongoing issues with the tire pressure sensors. The light comes on and will not go off. The first time it happened the dealership replaced the sensor. A week later it came on again, the sensor was replaced again. As I drove off the lot it came back on. The entire rim and sensor was replaced. It has continued to come on repeatedly over the years. In addition I have had to replace all 4 tires yearly as they wear unevenly, regardless of the brand. The back tires wear in a wave pattern, the front wear around the edges even after new tires are balances and aligned. I can not drive at highway speeds with the windows open because of the noise the tires make. It makes me sick to my stomach. With all the other sensor light, tire and suspension issues others are having I am surprised there hasn't been action taken. Tires are not an accessory part, it is a necessary part and when they fail people get hurt.