@englishlauren Try clearing Origin's cache and repairing again; sometimes it's necessary to force Origin to refresh its data before the repair will be fully effective.
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
If that doesn't help, you can delete the folder for the Paranormal pack and redownload it. This isn't the official way to uninstall, but at worst, redownloading and repairing should fix any issues. Inside the Sims 4 program files, usually located in Program Files (x86)\Origin Games, will be an SP18 folder, as in, the Paranormal pack is the 18th stuff pack released. Delete this folder, clear Origin's cache again, and you should be able to redownload the pack.
