My sims 4 game refuses to open.

@maxie2308  There are a couple of potential issues here.  The easiest intervention is to run the Origin reset tool for macs, and then disable Origin in-game.

https://help.ea.com/en-us/help/origin/origin/how-to-reset-origin-on-mac/

Another problem is that players who are still running OS Yosemite have been having trouble with Origin for a couple of weeks.  Updating to High Sierra will fix the issue, but for players on older macs that won't run HS, installing El Capitan instead can also work.  If you're not sure which OS you have, click on the apple in the upper left corner of your screen and select "About This Mac."  You can install a new OS through the App store—just search for the version you want.

If Origin itself starts cooperating but you still can't play TS4, you can drag your entire game folder out of Documents and onto your desktop.  When you launch the game again (if it launches successfully), a clean folder will spawn with no content.  Play in this folder for a bit, and if everything is working correctly, you can start moving your saves and other content into it from your old folder.  You may have a corrupt file somewhere, or an out of date mod or cc item, so test the game after moving each batch of content to make sure it still works.  If the game fails to load again, you'll know that you need to sort through the files you just moved over to find the source of your issue.

I UPDATED ORIGIN FOR THIS VERY REASON AND THEY ERASED ALL OF MY GAMES. EVERY SINGLE ONE OF THEM. 

This is a known issue and EA/Maxis is working to correct it. There is another thread open on the forum that addresses this issue.