I have not been able to contact EA, but after a little searching around I found that the free items (on the Sims 3 website) for registering Sims 3 and expansions online are also not working. (The game asks me to register the expansion, but my code is invalid since it was "used" when I bought the games through Origin.) Maybe there's just some other bigger Origin/registration problem? At this point I think the Sims 4 rewards aren't really worth the trouble, but thank you for the suggestion and I hope I didn't waste too much of your time!