Google services stopped...


AC Question

So a friend of mine tried rooting my phone and basically ruined it. I somehow installed the Unofficial CyanogenOS 12.1S. Then he tried installing GApps and ruined that too... I managed to download something that was google play services but every millisecond a pop-up message comes up and says "Unfortunately Google Play Services stopped". And it's repeating every freaking second... I've tried everything by now: clearing cache and data from the app, checking if the download manager is disabled, deleting my google account(which I could only do once. Now it doesn't even show it)... Everything the internet suggested.
So I come here desperate for help. If nothing will work I'll have to take it to a lab and get them to install everything RIGHT for me...
Thanks in advance.