My parents' safe deposit box was ripped off by Chase Bank in Sacramento, CA

My parents had a safety deposit box with American Savings and Loan in Sacramento, which was purchased by Washington Mutual, which was purchased by Chase. They've had this box since 1980 or so and kept some gold and silver coins and some savings bonds that were gifts to them from older family members who have since passed on.

My parents had stopped receiving a bill for the safe deposit box and called the bank to inquire about that. They were told that they no longer had a safe deposit box with the bank because they had been into the bank and picked it up four years ago and that the manager had used his/her discretion to open it up for them without my parents' keys to the box. My parents are in their late 50s, so their memory isn't what it used to be, but they do not recall picking up the box. They no longer live in Sacramento so it would have been about a three hour trip to pick it up. Also, the bank cannot produce any proof they picked it up, and, most importantly, my parents still have the keys to the box.

I'm so upset for them. My parents are really good people who have worked so hard their whole lives and they don't have a lot of money. They weren't counting on this for retirement, but it would have really helped.

Their next steps are to escalate this within Chase to management above the branch level and see what they will do to help them. After that, if the bank isn't helpful, they're not sure what to do next

Anyone have any suggestions?