This forum cracks me up sometimes. Send the insurance company a letter putting them on notice? Yeah, that'll scare them into doing the right thing.
From my experience, it boils down to the luck of the draw with the adjuster they assign to your case. Sure you can argue with them, point things out, tell them they're wrong, etc. but you'll end up losing.
Be nice, point out your concerns to the adjuster, and take what they give you. Unless you want to spend thousands hiring a lawyer trying to be made "whole."
I'm sorry you were in an accident, accept it, move on, get camping again, and enjoy life.