2021 GMC CANYON Electrical System Problems

While driving, a fire started inside the vehicle between the rear passenger side seat belt and the rear window. My daughters were in the back seat and started screaming. I immediately stopped the vehicle and ran to put the fire out by smothering and throwing water on it. There was zero warning...no lights or warning messages. No major injuries occurred (only small minor burns to my right hand). I then brought the vehicle to the dealership where it was purchased. I was told it was a known issue, and I was prompted to file a claim with my insurance company. Someone from the insurance company, along with the service department at the dealership, inspected the vehicle. Insurance has agreed to cover the parts damaged but not replace the part(s) that actually caused the fire. The dealership will address the actual problem, but only if I pay for the repairs ($1100-1500...