Hi @Mccrmjen You might want to try rebooting and testing iTunes again today just in case this was resolved on the Apple side as I believe @tutaix reported. I can't test this until I get to the affected machine.
If you still need to reinstall, you probably missed the step when you delete the file in the Terminal app.
While Terminal is open, paste in sudo rm -r /Applications/iTunes.app
It will ask you for your password if you're an admin - if your regular account is NOT an admin account on your computer (which is actually good practice!), you should simply log into your admin account and run that sudo account in Terminal to remove iTunes.
(You can also use a function called su to accomplish this from your user account but that's getting into the weeds a bit)
When you're done with the Terminal command you shouldn't be able to open iTunes at all or see it in your Applications folder. Then you're ready to install the older version. Remember to heed my subsequent posts about turning the App updates off and hiding the iTunes update app - that might be why it updated on you.