The contact owns a 2013 Ford Edge. The contact stated while the vehicle was parked, the gear shifter was shifted into reverse; however, with the contactas foot on the brake pedal, the vehicle rolled backwards. The contact depressed the brake pedal to the floorboard; however, the vehicle failed to stop. The contact activated the parking brake to stop the vehicle. The vehicle was inspected by several independent mechanics who confirmed a failure with the electronic braking system and brake master cylinder failure. The contact was informed that the electronic braking system and the brake master cylinder needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 34,000.