Go and pull your boat out today or tomorrow morning, but tell them YOU are pulling it, not them. If they complain, throw the "liability" BS right back in their face and proceed as SLOWLY and meticulously as possible (emphasis on SLOW) all the while saying "sorry" "I'm going as fast as I can" and "Let me check my plug /brakes / hitch ONE MORE TIME.
Then proceed to pull the boat up the ramp!

