The Sims 3 Supernatural Serial Code Not Working!

I bought Sims 3 Supernatural yesterday, but I downloaded it from the Origin Store. It works fine and everything but when I tried to register it on The Sims 3 website, it said it was invalid. I haven't used the serial code for another account, it's not a copy and I did enter it correctly ( several times ). Still no luck :-( Any ideas? Oh and also I got the Plants vs Zombies decor pack free with the game, and the serial codes for them worked fine.