You bought a game, second hand which is only activated and then tied to a single account?

Silly mistake.

I don't condemn you for buying second hand, but you should have done some research. Thats like buying a second hand copy of battlefield. Sure, you've got a game, but you can't use it.

No one to blame but yourself, or if you want a scapegoat, the guy for lack of infomation. He sold you a game, you bought it. Nothing illegal about it.