Crazy "System" traffic data - What to do? ios 9 - iphone 6s

I have a very limited data amount (only 1 Gb of 3G / 4G) per month

So natrually I took all the steps in order to limit my data drainage:

• Disable Wi-Fi assist
• Only five applications have access to cellular data traffic. Whatsapp, Messenger, Safari, google maps, and Mail. That's it.

Nonetheless, over the last 4 days, my data consumption was 394 Mb, apparently!! It's out of the question I used them all with the aforementioned application.

The only odd thing is "System Services" which counts for 460 MB! In that, I have a "General" amount equal to 359 Mb, 15.6 Mb of game center (! I never use it!) and 36 Mb of iTunes.

I want to disable all of that! What to do? Can somebody help?

I would look at which Apps are allowed to use Background App Refresh, in Settings > General & also possibly in Settings > iTunes & App Store what is allowed to download over Mobile data.

A third possibility is iOS updates themselves, which cannot be prevented; the best workaround for those is to always update on the day of release, through iTunes, rather than let the update download to the phone.

You don't have a neat switch to disable system data usage, but you can nip at the edges.

First, Game Center can be caused by the GC app as well as by games that make calls to game center on your behalf. I would sign out go Game Center entirely and see if that lowers the requests. You might have to delete the games that call against Game Center also.

Then you can reset the cellular statistics and keep a log of the items you use throughout the day and then review the cellular usage for system at the end of the day.

• Settings -> Cellular -> Reset Statistics

• Settings -> Cellular -> turn off Game Center and other items you never want to go over cellular data.

You can also turn off cellular entirely and see which apps complain the loudest about it. Lastly, I would go to notifications and remove all notifications from your lock screen that could use notifications over cellular. That will save battery as well as cellular data out of proportion to what you might expect (from my experience at least). It's tedious, but then adding in just the notifications you really need makes things much better.

iCloud>iCloud drive... this guy consumes data silently... Make sure its turned off.