Random Contacts saved in my iPhone 6 For a while now, I have noticed that my iPhone 6 will randomly delete contacts of the people that I know, and other weird contacts of people that I have never heard of suddenly appear at the same time.

I am fairly sure that it is not due to sync with Facebook or Twitter as I have never heard of these people in my life. It has been rather frustrating and confusing to have to re-save those people's contacts several times. 

Does anyone have any idea why this happens?
Check if either


You're logged in with someone else's icloud or email accounts in settings


or


Someone you know (kid, spouse, etc.) is using YOUR icloud account on their device.


Easiest way to tell: change your icloud password and see if anyone screams, and if the problem stops.

Another source of them might be if you share a computer and multiple people sync their phones to it, it might be syncing your phone book with the computers'