I've been victim of something similar, although it was eBay that picked it up, locked my account and emailed me asking me to contact them. Basically, a hacker had accessed my eBay account and listed an item for sale, but replaced my bank details with theirs. That way, a buyer would remit funds to the hacker and then pursue me for the non-existent goods. EBay then set me up on two step login (whereby they text me a single use PIN when I want to log in) and have assured me that my account will no longer be vulnerable to hacking.