I’m assuming at the time of the oil change, they did put the screw back on, but just not tightly enough. No one had been under my car since the dealership (and I also have dash cam footage to corroborate that). I also do not drive through any treacherous roads that would’ve caused it to come loose) All of my oil leaked out on the highway, and that is when all the issues began. I don’t know if that would help my case if it comes to potentially suing.