Re: EA has the WORST customer service

  This is the SimCity forum, not Sims 3, so there may be other things to try under the correct forum. SimCity doesn't require the serial codes to install on another computer, you should just be careful to log in to Origin on the same exact account, and all game expansions should be in your game library.

For a CD install of Sims 3, however, if you still have your old computer, you should be able to get your serial code from it. Log in to Origin, right-click the game icon and choose the settings button (under the download button). Click on Settings, then Game Properties, and the serial code should be listed there.

You can also find it in the registry (PC) or terminal (Mac). Complete steps for doing that can be found in the accepted answer here: https://answers.ea.com/t5/The-Sims-3/I-lost-my-registration-code-for-Sims-3/m-p/1689123/highlight/true#M90196

If neither of these works, you will have to go through customer support. Start here: https://help.ea.com/en/ and navigate through. I hope that you get your problem resolved.