2002 GMC PICKUP Parking Brake Problems

I FOUND THAT THE PARKING BRAKE WOULD NOT HOLD THE VEHICLE WHEN IT WAS SET WHILE LAUNCHING MY BOAT ON THE SLOPE OF A BOAT RAMP. THIS COULD CAUSE INJURY OR DAMAGE IF THE VEHICLE ROLLED WHILE SOMEONE WAS BEHIND THE VEHICLE WHEN IT BEGAN ROLLING. THE LOCAL DEALERS MECHANIC CHECKED THE PARKING BRAKE SHOES AND FOUND THAT THE LEFT ONE WAS EXTREMELY WORN WHILE THE RIGHT ONE WAS IN GOOD SHAPE. THIS INDICATES THAT THE PARKING BRAKE WAS NOT ACCIDENTALLY LEFT ON WHILE DRIVING BECAUSE BOTH BRAKES WOULD BE WORN. I WAS TOLD BY THE MANUFACTURER'S REPRESENTATIVE THAT THIS WAS CONSIDERED NORMAL WEAR AND TEAR AND THAT NOTHING COULD BE DONE TO COMPENSATE ME OR MAKE MODIFICATIONS SINCE THERE ARE NO RECALLS ON THIS MODEL TRUCK EVEN THOUGH OTHER MODELS HAVE BEEN RECALLED WITH THE SAME TYPE PROBLEM. THE VEHICLE IS CURRENTLY IN THE SHOP AT THIS TIME TO...