Legal Question in Real Estate Law in California

The starting point would be to research whether lack of notice was the fault of the bank, the post office, or failure of the owner to receive, open and read his mail. "Auctioned off without any notice" is a very damning accusation, and if true could lead to grounds to set aside the sale, but on the other hand, big banks probably don't make mistakes of this kind as often as defaulted borrowers make mistakes in receiving their certified mail.