Driveshaft problems of the 2007 GMC Yukon

I purchased a 2007 Yukon and since that time I have had the rear axle bearing replaced 2 times at 43k miles and again at 93k due to a humming noise extremely loud. Again the noise recurred at 123k miles I returned to dealer they refused to diagnose the problem because the warranty was expired at 100k. I mentioned that the noise returned for the 3rd time. Ii continued to drive the vehicle and a few days later while driving on the freeway w my daughter the car locked ( differential). The differential gears broke. . I had it towed back to the last dealer that repaired vehicle and they mentioned it was out of warranty ( which is why they couldn't inspect it unless I paid). I then took it to my home dealer where car was purchased and they discovered an intact screw when they removed the cover from differential. Mechanic noted that the previous dealer that worked on vehicle might have not tightened bolt correctly since bolt had no damage of threads and was intact. I then called gm customer service and they refused to correct problem. Service director did mention that axles could have shot out and caused fatal crash keep in mind my daughter of age 6 was in the car. Dealer (home dealer) still has vehicle and dealer that last repaired refuses to correct problem. It has been 1 year and 1 month since last repaired and mentioned if not tightened properly it would have already caused problem by now. Please advise if I have any alternative course of action the repairs exceed 5000. 00 dollars not including any damage to the transmission when drive shaft locked . . .

The transmission was leaking and recalled and that was fixed by gm. The brake lights sometimes over heat and I had to replace the saddles on them. I do not even know they go out but I have people honking at me that I have no lights in the rear. Now with my warranty out and have 86. 000 miles on it the fuel pump is out on the vehicle at a 700 dollar cost. The door knob fell off, I have oil pressure issues all of the time. Last November the drive shaft fell off as I was driving down the road and had to pick it up off of the interstate which someone could have gotten hurt. Brake issues. When you spend 48,000 dollars on a vehicle it makes you sad that gm does nothing to help their customers. Maybe the government should not help them anymore. Today they wanted me to take it to gm and pay 200 dollars for a diagnosis. Just more money in their pocket. I want to another shop for advise. This car is definitely a disappointment nd lemon.