Carrier/rack problems of the 2009 Buick Enclave

I bought my Enclave brand new. I now have 73000 miles on it. We took the car in because it was becoming very hard for me to turn the wheel and I could have been in an accident because of this. The dealership told us that the power steering pump and the power steering rack & pinion had to be replaced! what??!! I had never heard of anyone that I know of having this kind of major issue with their car at 73000 miles. We did some research and found that there have been several other Buick owners with this same issue with fewer miles on their car. This is a safety issue that Buick needs to research and resolve. My other safety problem is the power liftgate. If your car is parked on a hill, the power liftgate will drop on top of you with no warning. The liftgate struts dont work when your car is parked on a slope.