My wife´s 5c is used for WhatApp and mail, and no exotic apps are installed. She is a casual user and has a 700MB mobile data package. All worked well till this week. Suddenly her data was burned up, and going 1500MB over her limit, resulting in a 90 euro added to the bill. Strange thing is, and here I need your help, I see in the settings the data is going through "System and Document synchronisation". But it is ONLY doing it through mobile, not WiFi. I was suspecting iCloud drive, but that should be done via WiFi already? So I disabled WiFi and it started to sent data again over 3G. What setting could this be that ignores WiFi and only pumps gigs over 3G? I tried disabling iCloud Drive, WhatApp backup, all the photo's are already in the cloud. Problem is that I cannot see WHAT is being transfered, it is only "document and synchronisation" or "Other", not helping me at all. Anyone any idea? Any way to monitor what is being synced? iPhone 5c iOS 9.3.