2017 BMW X5 Parking Brake Problems

MY BMW X5 2017 HIT MY GARAGE DOOR AFTER I PUT IT IN PARK MODE. I BELIEVE THAT IT WAS CAUSED BY ITS TRANSMISSION PROBLEMS AND THE FAILED HANDBRAKE. ON THAT NIGHT, I STOPPED MY CAR ON A SLIGHTLY INCLINED DRIVEWAY. I TURNED ON THE HANDBRAKE, PUT THE CAR IN PARK MODE, TURNED OFF THE ENGINE, AND THEN STEPPED OUT OF THE CAR. ABOUT 10 SECONDS LATER, THE CAR ROLLED FORWARD AND HIT MY GARAGE DOOR. IT WAS SNOWING THAT NIGHT, BUT THE SNOW WAS LESS THAN ONE INCH. THE CAR DIDN'T SLIP BECAUSE THE FOUR WHEELS ROLLED FORWARD. I TESTED IT A FEW TIMES RIGHT AFTER THE INCIDENT AND THE CAR STILL ROLLED FORWARD WITH THE HANDBRAKE ON AND AFTER SHIFTING TO P MODE. THE TRANSMISSION AND HANDBRAKE FAILED TO WORK SEVERAL TIMES ON THAT NIGHT, BUT I CANNOT RE-GENERATE THE SAME RESULT SINCE THAT NIGHT. WHEN I SEARCHED...