2015 Chevrolet Traverse cruise control problems

I was backing out of my garage when all of a sudden the car started going about 50MPH and hit a tree in my yard, then the front end lifted off the ground and the car raced forward and crashed into my friend's car. They both hit my pickup truck also. All 3 vehicles are a total loss. From the neighbors who observed this, it's a miracle I wasn't badly injured. Also I have a tear in my achilles tendon on right foot so in no way could I have mashed on accelerator

The contact owns a 2015 Chevrolet Traverse. The contact stated while driving at various speeds, the vehicle speed unintendedly decelerated to 25 MPH. During the failure the message "Traction Off", "Engine Power Reduce" and "Stabili-trac" were displayed. The vehicle was taken to the local mechanic who replaced the accelerator pedal sensor on several occasions, but the failure had eventually reoccurred. The vehicle was recently taken to the local dealer who was unable to reproduce the failure.