Most likely a virus keylogger etc. Sounds like someone was trying to access your bank accounts and the bank has locked things down to safeguard your money.
It's an inconvenience I know, but it beats having empty bank accounts. I've previously had my credit card cancelled while on vacation back in Alberta because I topped up my rental car w/ gas, then went to Home Depot (needed supplies to help folks put up fence) and then to the grocery store (bbq that night). I had forgotten my cellphone in a date's car after the first date (I insist to this day it wasn't on purpose to get a second date, but we're engaged now so who am I to argue?) so the CC company couldn't get ahold of me, then they cancelled the card.
When I called in the rep explained to me that "when someone steals a credit card, the first three places they most likely purchase items at are grocery stores, home improvement stores, and fill up on gas"...
All you should have to do is show them two pieces of govn't ID and they'll give you your access back.