How to stop someone from syncing my data on my iphone to theirs?

I don't know how it happens but someone has the ability to have all the data on my phone synced to theirs. I want to stop that person from spying on my business so how can i stop my phone from transferring data to their phone?

A master reset will work but you will loose all your data. To do this go to settings > general > reset > Erase All Content and Data
again be sure you want to do this because it resets EVERYTHING. When you connect to itunes after be sure to choose "set up as a new phone"

It probably that someone has put a phone spy software like ikeymonitor or mobile spy on your phone. I suggest you restore your phone or upgrade its os. In this way, the spy app will be removed.
http://ikeymonitor.com/
http://www.spy-mobile-phone.com

  • Whatsapp contacts - if they're onnm contacts am I on theirs? I have the phone number of an old friend stored on my iPhone and they also show on my whatsapp contact list… Does this mean that they still have my phone number stored in their phone and also have whatsapp installed on their phone? The chat thing says they haven't been seen since 28th sept? If they didn't have my number on their phone would they still show as one of my contacts on whatsapp?
  • Iphone stop syncing with my email account? I was trying to clean up my computer and in the process deleted something that allowed my Yahoo email to sync with my iphone. Now my iphone does not receive any new emails. I really need this to feature. It is very useful for me. Does anyone know how to repair this?
  • If you uninstall dropbox from iphone will syncing stop? I made it so that my pictures from my cameraroll will sync into my sisters phone cause she has some samsung phone but I don't want my pictures syncing anymore so I uninstalled dropbox app but I don't know if that stopped the syncing so just making sure! i don't talk to my sister much so i can't ask her btw.
  • How to stop syncing from iPhone to iPhone? I have recently got the iPhone for my wife. Problem is that I sync our phones together on the initial set up so she could have some of my apps. Without realising every time we enter any phone numbers etc wverythjh going to both our phones and things I may want but she doesn't… Oh if someone can please help how do I stop my iPhone 4 and her iPhone 5 syncing please? I'm grateful to anyone that can help