Re: Sims 4 EP purchased from Steam
@gamerdudeForever If you buy content on Steam, you'll need to uninstall your EA App version of Sims 4 and install the Steam version. You could then download your EA-owned packs into the Steam-installed base game, and everything would work together.
As for purchasing from EA, try using PayPal instead. I know it's not a perfect solution, but it might help here. And feel free to leave feedback in the EA App forum about the lack of a shopping card. Plenty of others have, and who knows, something might change eventually. Or not.