nope its not possible for you to do that.... but try sending in a suport ticket, in the past they have issued a new cd key to others that have done the same as you. but that means everything made on that account will be lost.
Be prepared for automated responses at first, just continue on with the support ticket until you get a live person to discuss your issue. As Darkk stated, there have been reports of similar mistakes being remedied in the past (assuming you just bought Factions and aren't talking about a separate account you've held for a year!).