2015 BMW Z4 Power Train Problems

I HAD A VERY FRIGHTENING TRANSMISSION MALFUNCTION ON SATURDAY, MARCH 7 IN MY 2015 Z4 (THREE MONTHS OLD). I WAS HEADING DOWN A SLOPE INTO A PARKING LOT AND STOPPED TO PICK UP A TICKET AT THE KIOSK. THE CAR WAS IN DRIVE AND MY FOOT WAS ON THE BRAKE. ONCE I GOT THE TICKET, I TOOK MY FOOT OFF THE BRAKE AND THE CAR STARTED DRIVING BACKWARDS! I STOPPED IMMEDIATELY (LUCKILY THERE WAS NO ONE CLOSE BEHIND ME) AND TRIED AGAIN. SAME THING. SO, I PUT IT IN PARK, THEN BACK IN DRIVE AND IT DROVE NORMALLY. FINE. FROM THERE, I HAD TO GO TO THE STORE. WHEN I GOT THERE, I TURNED OFF THE ENGINE (AND THE KEY WAS IN MY PURSE) AND, OF COURSE, IT WENT AUTOMATICALLY INTO PARK, AS IT ALWAYS DOES WHEN IT TURNS OFF. SITTING IN MY PARKED CAR, I WENT TO GET SOME...