@Katieboo117 It's normal for worlds to show as objects as they download, and even immediately after the download is finished. I usually need to wait 10-20 seconds longer for the thumbnail to change to the world preview, and only then does the item install properly. So please try that.
If that doesn't help, try again in a clean user folder. Move or rename the Sims 3 folder in Documents > Electronic Arts, open the launcher to generate a new one, and install one of the worlds there. If this works, install the other world as well. You can then move your saves and anything else you'd like to keep from the old folder to the new one. Here's a summary of what you might want to transfer:
https://answers.ea.com/t5/Store-Issues/Read-First-Sims-3-Store-guide/m-p/13479922#Clean
There's a way to combine your previously-installed Store items with the new ones too, but I would suggest installing those items fresh and leaving behind the old copies. When an item doesn't install properly, it can corrupt the file it's in and prevent other items from loading. Still, if this would be a burden, let me know, and we can try to salvage your existing installed content.
