The contact owns a 2021 Ford Bronco Sport. The contact stated that while the vehicle was in reverse(R), there was an abnormal screeching sound coming from the rear brakes while depressing the brake pedal. There was no warning light illuminated. The contact had taken the vehicle to a local dealer and an undisclosed recall repair was performed; however, upon retrieving the vehicle, the failure worsened. The dealer was notified of the failure but offered no additional assistance. The manufacturer was notified of the failure and referred the contact to the NTHSA Hotline to report the failure. The vehicle was not repaired. The failure mileage was unknown.