VEHICLE WILL NOT HOLD AFTER THE SHIFT LEVER WAS PLACED INTO PARK POSITION ON INCLINE. CAR WAS PLACED IN PARK AND ROLLED BACK, DRIVER DOOR HIT DRIVER AND DRUG DRIVER ABOUT 20 FEET ON PAVEMENT. PASSENGER IN CAR VERIFIED CAR WAS IN PARK. PASSENGER WAS HIT IN BACK. CAR CONTINUED TO ROLL DOWN FIELD, ACROSS ROAD INTO ANOTHER FIELD BEFORE STOPPING. WITNESSES WHO WENT TO CAR VERIFIED CAR WAS IN PARK. CAR WAS TOWED TO EMPIRE CHEVROLET IN WILKESBORO, NC. SERVICE MANAGER NELSON GREER TOLD ME NOTHING IS WRONG WITH CAR. FOUND GM SERVICE BULLETIN P11360A & D OUTLINING THIS COMPLIANT AND MEASURES TO FIX. NELSON GREER REFUSES TO REPAIR. CAR IS UNDER WARRANTY.