@SimCryptid You can try installing Origin from the link here:
Make sure that the EA App is closed and that the EABackgroundService isn't running in the Task Manager; it would be under background processes.
If Origin works, try repairing Sims 3: right-click on the game tile and select Repair. If Origin doesn't run properly, clear the EA App's cache:
https://help.ea.com/en/help/faq/clear-cache-to-fix-problems-with-your-games/
and repair: open My Collection, hover over the Sims 3 icon, click the three dots, and select Repair.
If that doesn't help either, please let me know where you bought these packs, and if you have discs, whether you installed them via disc or downloaded them from Origin or the EA App.
The store content issue may be fixed now, but you'll need to delete the existing files and reinstall. Please see this post for more information:
Keep in mind that deleting the Downloads folder will remove all downloaded Sims3Packs, including custom content; deleting DCCache will remove all content installed through the launcher, including cc; and that deleting InstalledWorlds will remove any custom worlds. You should definitely delete the DCBackup folder regardless. If you don't want to remove your cc, go into DCCache and delete everything except the files ending in .dbc, delete the store content downloads inside Downloads (or put the entire folder somewhere else), and only delete the worlds inside InstalledWorlds that are from the store.
