I have a similar problem after converting my game from Steam to Origin. I uninstalled the Steam version, then installed from Origin. From within the game I noticed that my store items were missing, so I came out and even though they were still downloaded it wouldn't let me reinstall. So I deleted all store content from the startup game panel, re-downloaded them from sims3.com, and reinstalled them.
However when I go into my game the items are still missing. They are not even in the buy menu so I can't even just buy them back for simoleans. And they do not even appear as unbought store items, so I have no idea what to do next...