I had this happen to me a few times too. One time it was a spam bots post that it claimed I was following. I still have copies of the emails if there is anything in them that might be helpful.
The above is all just my opinion on what you should do.
As with all advice you find on a random internet forum - you shouldn't blindly follow it. Always test on a test server to see if there is negative side effects before making changes to live!
I recommend you NEVER run "random code" you found online on any system you care about UNLESS you understand and can verify the code OR you don't care if the code trashes your system.