Invalid Registration code??

So, I have been kicking around the idea of getting back into mmo's and I tried several, last of which was eso.... When I came across FFXIV and their free trial offer I gave it a go... I really enjoyed it, so I decided to purchase this game. That's when the confusion began... I wasn't sure which product to buy, I saw Heavensward which is the expansion (I think) for FFXIV online.... so i purchase the pc version for 39.99 and get the verification emails and the registration codes, but when I go to register it tells me the code is invalid.... and apparently today is a holiday so no customer service is available until next week.... not sure what to do now....