Vehicle Speed Control Related Problems of the 2015 Mini Cooper

Vehicle Speed Control problem

I made a right turn from the main street, into the parking lot of a strip mall, then an immediate left turn, and another right turn into the right angle parking slot. All the while having my foot on the brakes, I started to shift into park, when it was in the right spot. The Mini instead coming to a stop, revved up, jumped the curb and hit the store in the front. The air bags deployed. I had my foot on the brakes really hard, all the time but the brake pedals were locked up. It would not move up or down. Sat hard on the floor! when the tow truck came, the brakes were still locked up and the gear was in park and couldn't be moved from there. The seat belts couldn't be retracted either. Mini engineer claims that there is nothing wrong with the car and I can safely drive it after the body is repaired. I am having a difficult time with this conclusion. The car's brakes and gear were locked up, and had to be lifted on a flatbed and taken to the repair shop; I still maintain something within the car malfunctioned.