Wait .. maybe I got it wrong or you guys got it wrong but .. if it's your old cd-key and you didn't play with it for some time, then after the reset of the heirlooms, weren't all chars put to alt and you had to pick one to main ? So if you played with a new cd-key recently and haven't played with your other cd-key , it means your "main" got switched to an alt but can theoricly be put to a "main" .. Check in your character page at the bottom, maybe it's not too late to put it main, and if you're other cd-key is main, then you should be able to trade gold...