Hey Hey--
I have a Mac too and I've dealt with this. 🙂
I have a couple of questions for you:
-What version is your operating system? It must be higher than 10.6.8 for it to be compatible with Origin.
-Have you tried uninstalling both Origin or the Sims games (you mentioned one but I wasn't sure which)? Also, did you do a clean, uninstall of it? (to do this on a Mac you would've had to go into your hard drive and delete extra stuff, not just delete Origin from your Applications folder)
--->to do a clean uninstall of Origin on a Mac, remove Origin from the Applications folder and delete the folders listed here: https://help.ea.com/article/how-do-i-manually-remove-a-game-from-my-games-on-origin-using-mac
--->to do a clean uninstall of the Sims games on a Mac: http://bluebellflora.com/ts3-on-a-mac/how-to-do-a-clean-uninstall-and-reinstall-on-a-mac-2