Account Hacked but they bought RP on my Account????

Okay so a couple days ago, my account got hacked however... someone purchased RP repeatedly on my account instead of actually taking things. So it wasnt my actuall account that was hacked i think it was the credit card i saved into the account. But it was weird because the CVC needs to be typed in everytime. I have no idea how this could've haappened. I'm just curious as to what actually got hacked and how.