Brake Electric Antilock problems of the 2002 Jeep Laredo

Since I bought the vehicle, the brakes have not been "right". I took it in a few times to be told nothing was wrong. I was in 2 accidents, where the vehicle would not stop, and rear ended each vehicle. When I braked at speeds over 50 mph, the front of the vehicle shook. In Aug. 04, I called the dealer again to complain, and was told the brakes are not under warranty (2002 grand cherokee Laredo - 26000 mi) I finally took it to my private mechanic, who told me that he has replaced numerous brakes on this model - they seem to be out of alignment from the start. My insurance company dropped me - too many of the same accidents in the last 2 years, and am now paying high rates, as a result.