Sims 3 code already redeemed

@coops200000  Please make sure you don't have any filters enabled in your game library; the filter function is in the upper right corner of the Origin window when viewing the library.  Origin was down a few hours ago, so it's possible that it wasn't loading your content correctly.  You can also try clearing Origin's cache to make it refresh its data.

https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/

If you're sure this is the same Origin account in which you originally registered your content, you can try contacting EA customer support and asking what happened to your content.  You can access your purchase history by hovering over your username and selecting EA Account and Billing; that will take you to an ea.com page with an Order History tab.  (Make sure it's set to display all purchases, not just the last three months' worth.)  I believe that registering a game also shows up as an event on that page.

With the current situation, EA support has reduced hours and functionality, and there have been long waits for help.  Phone calls are unavailable entirely, but live chat is open from 9 am to midnight GMT, Monday through Saturday.  You should be able to upload a screenshot of your purchase history to a chat session; if you originally bought discs, it would also be helpful to provide photos of your discs, cases, and inserts with the codes printed on the backs.

https://help.ea.com/en/contact-us/

Otherwise, if you do have discs, the best approach may be to do an all-disc install.  Disc drives are cheap these days, certainly a lot cheaper than rebuying all your content.