If this is all content you purchased from the store, then uninstall it all in the launcher, redownload it from the store and reinstall it. If that doesn't work, then you need to take it up with EA, not MATY.
*** Well, but I was actually hoping to get a useful answer, which is why I asked here and not at EA. Figured people here would know better what to do, and would actually tell me (and btw, I tried uninstalling and redownloading before I made my original post).
If, for some mysterious reason, you cannot complete all of these steps, then perhaps your store items are exactly the kind of custom content they are already talking about in the thread I previously pointed you towards and to which you were too stupid to shut up and go.
*** Actually, I'd already looked at that thread before I made my post, which is why I'm not having trouble with any of my custom content. But I can't see anything in that thread which deals with Sims 3 Store content, only custom content.