Hacked?

In my experience, if your account was "hacked" it would have been completely stripped of anything of any value. It's possible it was used as a farmer/bot account if you didn't try to take control of the account back, but the fact that nothing is missing and nothing has changed other than a few more bg points kind of goes against the grain of that idea. It's possible you just got lucky.

The credit card was probably just a stolen card card, no one in their right mind would attach their own credit card to an account they stole.