If the value of your goods was estimated to be $40,000, you would do well to speak to an attorney in your area for a personal review.
If you did not notify the facility of your consolidation of goods from three units to one, it is possible you were still being charged for the other two units - leading to a default in payments.
An attorney can review your contract and assess the facts that led to the auction to see if you have legal recourse.
Were your belongings insured?