I am very disappointed with the purchases for this game. I had a similar problem trying to get my preorder bonuses to work. In fact I never did get my preorder bonuses to work with this game and I believe it was because of some issues with the login names that gamesas website uses. I think that somehow the game does not recognize the website login or it doesn't think it's the same login. I might be wrong, I'm just guessing. However I do use the same login name in the game as I do for the gamesas website. But it makes not diffference.
So I do not know what to do so that I can actually purchase the DLC. Any ideas? I don't want to change my login or nickname because I'm afraid all my progress and stats will disappear.
If you cannot fix this problem then I guess you lose another DLC sale.