I feel your frustration, @GalacticGal ! I held off as long as I could but someone else also uses the gaming rig, and I found EA App there the next time i wanted to play on that, and at first, it only showed one single compilation of store content for sims3 that I owned. The rest, vanished. The next time, I found more. I followed directions to get Origin on again following a link EACade gave us, so now my system has both origin and the ea app.
Then found through the ea app, a way to download all my store content. Yay, but no...about half of it said download failure that I didn't own that. Grrr.
Then the next time I went to play, all the store content I had managed to successfully download and install the last time, was again unistalled.
I hear others are having similar issues.
Sure hope EA is working on this, because they do download way faster through the ea app than they ever did through the soms3 store, but that doesn't help much of we can't access half our stuff, and must reinstall everything else, every time we play.
I have faith that they are working to resolve this and once they do, sims3 will be better than ever! Until then, bummer.