Re: Expansion not showing in library to download
@ndf2013 Please open the EA App game library, click Sims 4, select Manage > Manage add-ons, and let me know what you see. Is the missing pack listed there, and if so, do you see a Download button or something else? If the Download button is present, does it work?
it's also worth clearing the EA App's cache, which removes files not covered in a standard uninstall.
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
I'm not sure why a support rep would tell you not to uninstall and reinstall Sims 4, and I think that's the logical next step if you can't download the pack from Manage add-ons. Before doing so, make a backup copy of the Sims 4 folder in Documents > Electronic Arts. This folder holds your user data, not the game's program files, and while it shouldn't be deleted during the uninstall process, that has happened on occasion. So it's best to have a backup just in case.
On the other hand, if your missing pack isn't listed in Manage add-ons at all, reinstalling isn't likely to help.