Originally Posted by
Crimen
OK, I'm sorry, but I am having a hard time understanding. So you already own ARR on Steam, right? If this is the case, by default you have to buy Heavensward through Steam. However, you're saying that the code from Steam doesn't work? You say that SE is saying that you have to buy it from elsewhere. Was it an error of some sort that you got or what? Where did you get this information from? Just trying to figure out what's wrong. I don't think that the fact that you have a 1.0 account has anything to do with it since you can link multiple versions of it (Ps3/ps4, etc) and it shouldn't affect your account, that I know of.
Edit: If it's what Neri said, then yeah. You can't get the expansion through steam unless you purchase the game itself through Steam as well. Why? Not sure, but that's how Steam has it set up. Their suggestion is the best way to go.