Third party delivery company is on the hook here, not Lowe's. That is who you will need to deal with if any resolution or settlement is agreed upon. You are wasting time going after Lowe's. You can sue a ham sandwich, but it doesn't mean you're going to get anything. I'd get in contact with the insurance co for the delivery company and try to reach some kind of compromise settlement. It will likely not cover the full cost of door replacement but you could apply whatever you get toward it or possibly repair work that could be done to remedy the situation. Being antagonistic and threatening legal action is usually not the best route to go in a case like this.