IOS 8 High Cellular Data Usage

So my wife and I average about 8-10GB of data on a 25GB monthly plan. We have both had iPhone 6's for at least 4-6 months. This billing cycle we started getting text messages that we were over our data limit. After calling AT&T and looking at the data, they informed me that they are getting a lot of these calls so it appears to be a major bug. My phones were using a ton of data every 3 hours on the hour and my phones are on wi-fi 95% of the time. Unfortunately AT&T was not able to do anything about it. They suggested I take my phones to Apple and have them looked at. At this point, I am ready to just go to a Note 5 when it comes out.

I just upgraded from IPhone 5 to 6 on Friday Aug. 21. Saturday I got a text saying I was already at 75%. Yesterday I got another one saying I've used all my Data and was charged $15. I know this is a mistake I barely used the phone since Friday and only connected when I was on WiFi!

I'm not sure this has been addressed or if it was my problem. Maybe someone could shed some light if this is possible. But after going on different forums and trying to get answers. I then went into Usage - Manage Storage - ICloud Photo Library. There under backups I noticed that I hade TWO phones listed: "Peggy's Iphone" and "Peggy's Iphone This IPhone". Apparently my IPhone was backing up AND most likely using data on both the Iphone 5 AND my new IPhone 6. I had ICloud backup on all along. I disabled everything turned usage and everything else off on IPhone 5. And deleted that old backup on the new phone. I also deleted my email accounts, apps and contacts on the old phone. I wonder if this was my overage problem. I had everything transferred at the Verizon store. You would think the rep would have gone into that setting and delete the old IPhone backup. So frustrating! I sometimes wonder if this is done on purpose to make $$$$$. I wonder if I can get my $15 refunded.

Same problem here on iPhone 6, AT&T, iOS 8.4.1

I've gone from an average use of about 1GB per month to almost 6GB this month without changing my phone use at all.

My data usage according to AT&T has been spiking (between 10MB and 600MB) at exactly 6AM, 12PM, 3PM, and 9PM. For two of those spikes, I'm on wifi and for all of them, I'm not doing any streaming or even really using anything on my phone. I've turned off the following and will post back if it helps:

• background app refresh for almost all apps
• Settings -> Privacy -> Location Services -> System Services ->: everything but find my iphone OFF
• all iCloud drive stuff, including documents and data
• icloud backups and everything but keychain and find my iphone
• handoff
• almost all location services
• all app store automatic downloads
• fetch (for mail)

that said, it's very stupid to have to turn off all of this (expensive and hi-tech) functionality just to keep the phone from leaking cellular data.

Those aren't actual data spikes - they are summaries of the data used in the last period. This is done to make reporting a little easier.

Besides any runaway app, it seems like getting a new SIM card has solved the issue for many. I had a iPhone 5S that was completely fine until I gave it to my daughter and they put a new SIM card in it. Suddenly, data usage went through the roof. Resetting the iPhone didn't help nor did re-seating the SIM card. Eventually, we traded it in for an iPhone 6 and have had no issues since.

I had the same thing happen to my iPhone 6 and after I took out the SIM card and placed it back in and reset the phone, I had no more data problems.

AT&T as well, and I've no cloud involvement. Wondering if it has to do with an update as I've never experienced this before. Maybe the last 6 weeks or so..

I'm using an ipad mini on 8.4.1 with Virgin media and this had rendered it all but useless when out and about. The has only occurred within the last month.

i did reset the phone but still facing the same problem.

Maybe the only option is a class action lawsuit to recoup all our overage fees.

So what did you do about the leaking data problem?

For those of you that upgrade to IOS 9.0.1: be aware that you need to go in and change some settings to avoid overage charges:

The primary one: Settings --> Cellular --> Wi-Fi Assist: Turn it OFF. This is a feature that allows your phone to connect to your cellular network automatically if it detects that your wi-fi connection is "weak." The justification is that people who have an unlimited data plan won't mind having this feature so that they can browse faster. However, those of us in the real world know we're being muscled to drop or we're being prevented from continuing those grandfathered unlimited plans.

Also check the new apps that have been installed or updated after the update. Despite my having turned off all cellular connection to many of them, after the update they were turned back on.

Thank you maryv820! Bought my first iPhone 2 days ago, 6+, by the time I got home with it I had used 131MB of my 150MB plan, got warning from carrier (Consumer Cellular), bumped my plan to 500MB. Today I have read most of this thread and turned off everything that was suggested, jumped to latest post Sep 29 your post, turned off Wifi Assist - I never would have scrolled down far enuf to see it but for your post. Now we'll see what usage I get while using home wifi. A great help.

That's like calling someone to fix a leak in your roof and having them tell you to tear down your house and build a new one.

Same issue. Message from Verizon at 4:04pm "You're almost out of data. You have 10% remaining w/ 5 days left...". The phone was on my desk unused at the time with no apps running and Wifi in full effect. At 4:47pm "you're out of data, you've been charged $15..."

Rude!!

Followed the thread here and am going to troubleshoot, but if apple & carrier are both passing the buck, where does that leave us all?

Thanks for all who posted solutions.

UPDATE: thank you for the info about settings>Cellular>wifi assist. OFF!!!