bamjorja Codes can't be used more than once, even by the same person in the same account. But are you sure you're in the right account? It's a very common issue to login to the wrong one now, with the EA App rather than Origin. Try any other email address you have access to and see whether there's an EA account attached to it; you can click "Forgot your password?" to get a password-recovery email.
If you can't find the right account, contact EA customer support with the codes that don't work and ask for help. A support rep should be able to look up the codes and may be able to help you figure out what you did with them.
I would strongly suggest using the live chat option rather than email. If you don't see it, try this link:
https://help.ea.com/en/help-contact-us/?product=the-sims-3&topic=missing-game&category=manage-my-account&subcategory=find-missing-game
Make sure you're signed into an EA site (this one is fine) before clicking the link and that the location in the lower-right corner of the browser window is set to U.S. or U.K.
Alternately, try using the help site without being signed in. Some categories of issue allow you to proceed without an active login, and many of those offer the live chat option.