Firstly: restart your game, then head back into the in-game store. If any transaction is pending, doing this should finish everything off and make the cells available for use.
If this does not work - please get in touch with us straight away with your Player Cloud ID so we can investigate further.
If you are a PS4 user we'll also need to know if your game and store regions are matching. If you're not sure about this, check the in-store page. If you see a message stating "no packs available" (or words to this effect), let us know.