Lost account and Sims 3

 do you have two orign accounts and maybe logged into the other one instead ? you can contact CS to assist with lost/forgetten/merge accounts

FAQ how to find your code  http://answers.ea.com/t5/The-Sims-3/FAQ-Lost-and-broken-DVDs-and-missing-serial-codes-What-to-do/m-p/14230#M1304

FAQ inculdes a section on games not showing up in orign 

http://answers.ea.com/t5/The-Sims-3/FAQ-Invalid-and-Used-Serial-Codes-amp-Games-not-showing-up-in/m-p/194028#M8203

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