e shows in Origin but not in The Sims Resource.

• It should auto-register to thesims3.com once you make an account here but you'll find the code by clicking on the game in origin and choosing i. If it didn't auto-register, you need to contact a game advisor (see below)
• The Sims Resource is a third party site that has nothing to do with EA.
• You don't need the email since the info is on Origin itself.

Game advisors can be found through live chat.

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
   

In Details here: How to contact a Game Advisor using the new EA Help page