I think you would be better served after repairing the damage to go with an RV insurance company of good reputation. It will probably be more expensive
But if they cannot show you in your policy where it is excluded I would be in touch with your state insurance commissioner.
Put all communication in writing to your insurance company. Ask for the place in your policy where the cause of the damage excludes their paying the claim. If they cannot prove to your satisfaction that it is excluded then the State Insurance commissioner can help. The insurance companies dislike hearing from the insurance commissioner and HAVE to cooperate with him they do not HAVE TO cooperate with a lawyer.
I New York and other states your coverage may be reduced if a repair is not made. And in New York if you repair it yourself you have to go to a place that will take a picture and send it to your insurance company