Re: lost Product Code for sims 4

Are you sure you're in the right account? The code sticks to the account you first use to install the game with. 

If you are, give these a try:

The game no longer shows up in Origin

Try the following things: 

• Restart Origin.
• Log out and back in and use the email address instead of the user name. Make sure to use the one you used to register the game in the first place.
• Reinstall Origin.
• Restart your router/modem.
• Make sure the game isn't hidden by accident. To check, put the filter to Hidden Games. If it's there, right-click on the game to unhide ((click on the spoiler below to view an exemplary screenshot))
  
  Spoiler

  
• Get in touch with an EA Game Advisor.

Source: http://answers.ea.com/t5/The-Sims-4/FAQ-Serial-Codes-Game-Activation-and-Download-Issues/td-p/4228232