My question involves personal property located in the State of: tenn

My mother was renting a storage unit, she fell behind as she has before but caught it up to the point were things were not in danger. I went to go get my winter clothes and when we got there there was another combination lock in place of my lock. we talked to the owner and heconfirmed he sold it a week prior, this was the wedsnday before last. when we told him we did not know it was up for auction he said he sent a certified letter and would get back to us with the number. he of course did not, the power office said they would have evidence that he did and we just plain diddnt receive it. I am one million percent sure it was not sent because i was checking the P.O. box, questioned her about the storage often enough, and she continued to pay him after it was supposedly sold. she owes me 200, 150 on the locker, she had given him 100 to kill some of the above numbers off at the end of august but she did not receive a reciep like she usually does. he took a two month vacation. when he gets ready to clamp down for non payment he adds his lock. there was no lock on it from him days before i last saw it. hes been back peddling the whole time, what is my legal recourse, what is his obligation, and how do i go about pricing the items we lost, what they'd be worth now or if bought new?

I hope this is the right section for this question, my apoligees if not.