@vochick Your issue is a bit different and, as far as we can tell, is unrelated to whether you own the "starter pack" or not. A couple of players have had success either using filters within the Origin app or buying through the website instead. Perhaps one of these techniques will work for you as well:
https://answers.ea.com/t5/The-Sims-3/You-already-have-all-the-games-in-this-order/m-p/7187687#M233177
If these steps don't help you either (and it might be useful to clear Origin's cache or uninstall and reinstall it; see my comment above for the links), please click Me Too on the initial post and reply describing what you've tried and which packs you can't buy. The more people post, the better chance there is that the issue will be resolved. (I wish it didn't work that way, but it does.)
