the codes should be redeemed in your the sims 3 account then downloaded from there once download install them if you redeemed the codes in origin first that can make the code invalid/used if that happened you'll need to contact CS
Guide to worlds includes instructions how to redeem in the sims 3 account
http://answers.ea.com/t5/The-Sims-3/Guide-Sims-3-Store-Worlds/td-p/1589911
if in the event you need to contact CS
1.https://help.ea.com/en/contact-us/
2.Click on the orange NEXT button
3.Select a platform
4.Click on the orange NEXT button
5.Select a topic and describe your problem in a few words
6.Click on the orange NEXT button
7.Click Chat Now to chat with a Game Advisor
guide on how to contact CS
http://answers.ea.com/t5/Beta-Archive/How-to-contact-a-Game-Advisor-using-the-new-EA-Help-page/td-p/2161281