That's exactly why I will never use a bank card to purchase anything where there isn't a direct line between me and the bank handling the transaction. A lot of online retailers retain credit card information, which IMO, should be illegal. There are a lot of sloppy programmers out there, and a lot of fraud has happened as a result. So the credit issuers added that three digit verification code. The stupid retailers are recording that, too.
Now the banks change the verification code with every re-issue, and provide monitoring as an add-on service.
Sorry to hear you've been e-robbed, my friend. I hope your bank is a good one, and they offer to cover this crime through depositor insurance. At least with a credit card, you can dispute it. Here's to hoping the matter is resolved in your favor!