Vanderbilt Trying to charge me twice Maryville Tennessee

My father recently passed away and he had mortgage through vanderbilt. He has been paying on his mobile home for ten years now at $500 a month. The original price of the trailer was $42,000 and with interest it came to $49,000. I went to the company to give them his will and death certificate and I was promptly told that I owe $37,000 on the trailer that was poorly built and has water damage and should be condemned and the insurance they provided my father wouldn't fix because he was hospitalized for almost the entire previous year. But they always got their payment and the insurance was always paid for. This isn't right. Please someone tell me what to do.