Log-in issue after release

I Preordered FFXIV off of Amazon, and was able to play early and was able to play the game perfectly fine. I stopped playing for a few days because I moved into a new place and now when I try to log in it is asking me for a registration code that I never got. I checked all of my e-mails and I cannot find any mention of it. Someone had told me that there was apparently a fix for this on the forums but I cannot find it. I just find other forums with the same issue and no response. Please advise :)