I had this problem, too. I don't know if this fix will work for everyone, but it worked for me.
So what my game did (and I don't know why it did this) is put the packs' folders in the Sims 4 Create A Sim Demo folder in the "Program Files>Origin Games" folder path. They should have gone to the "The Sims 4" folder. I had to drag and drop each pack folder to the Sims 4 folder from the Sims 4 CAS Demo folder. After I did that, the packs showed up as installed and showed up in my game.
The pack folders use the number instead of the name (for example, a folder might be labeled "EP14" instead of "Horse Ranch"), so you'd have to look up a list of the packs' names with their corresponding numbers, since I don't know if we're allowed to post links here.
@Kaleiliegh This worked for me. Thank you so much for figuring out this solution and sharing it with others!
