Only the base game shows up in the myGames tab (even after resetting and logging out and back in), when I put the product code in, it only tells me that the code has already been used, there aren't any error codes.
Then I'm afraid you'll need to contact customer support so they can take a look at your account.
They can be found here: https://help.ea.com/contact-us
Choose a category, a game and a platform for the contact options to show up.
If live chat is gray, change your country to US and make sure you're on US Business hours. It might also gray because they're very busy. Try later.
See this post if you have trouble with the site: http://sims3.crinrict.com/en/2012/10/how-to-contact-ea.html
