Just found the right front corner of roof is spongy and starting to leak. Nothing has been dropped on it, and have not hit anything. No other signs of anything hitting it or damage. Have extended warranty but RV Service Dept says not covered. Tried turning it into my insurance and they denied claim saying no signs of collision damage. Insurance company said they have seen this on other coaches. Any suggestions on how to proceed other than having to pay out of my own pocket?