TheEnigmaticT: While I am entirely unaware of any method that could resulted in a security leak on our end that would compromise your financial data, I've passed this issue over to support with a "please investigate immediately" flag. You will hear from them shortly. Sorry to hear about this.
TheEnigmaticT the OP didn't clarify whether his card was actually used fraudulently or if the bank had flagged potentially fraudulent activity and then blocked his card....
As an example - over the weekend I purchased Populous and Populous II ....
As sometimes happend the bank (Barclay's in my case) freaked out at this overseas purchase and flagged the account as having potentially fraudulent activity (this has happened before... my wife and I have yelled at the bank on multiple occasions about this)....
The first we knew of the block was when attempting to pay for groceries at Tesco's yesterday.... needless to say it's somewhat embarrassing to be asked for 'an alternative form of payment' for your monthly shop.... took an hour of arguing on the mobile phone with Barclay's to get them to remove the block and allow access to our money so we could complete our shopping....
Obviously there was no actual illegitimate fraudulent activity and the flag was - as usual - a false positive.