Likewise - I bet on Facebook, or...Mailonline. My g/f uses those two (no more than average), but she has settings for MO set to update on wifi only (but I think its only the pics). I'll check her fb settings this weekend. Apart from those two she and I use data for the same reasons, and whereas I use 80-90Mb a month, she uses 400-500Mb, and (as mentioned before) she has the mysterious overnight huge usages, she's ALWAYS asleep, and anyway ALWAYS hooked up to wifi.
Apple and O2 need to put their heads together. Apple should be responsible for apps creators they have vetted, and its O2 who are billing us ! Two words for them...CLASS ACTION.
So how come those of us who don't use Facebook have also suffered from this?
My own view remains that it is simply a scam to get customers to buy bigger data allowances. I did, partly because I could not afford to have O2 curtail my account for several weeks again, but partly because I wanted to tether my iPad to the phone and expected bigger use in future. Since then, I have had no problem - BUT my data usage has actually hardly ever exceeded my original contract allowance.
If it's any help, Dataman keeps accurate records of my usage. I left both 3G and WiFi on by mistake the other night (30-31/5/12) although the only apps on were Dataman and Onavo, which I leave on permenantly.
The Wifi used 242.1Kb whilst the 3G used 16.5Kb. I then checked the App Watch function and the only app showing up was 'Push Service".
Most nights I turn off both WiFi and 3G, and I've said before I only turn on 3G when I leave the house and then if I know I'm going to need it. Push service seems to be on all the time and it takes data at a trickle which if it's plugged in charging, is always on WiFi.
I regularly check my usage with O2 and it is still showing on the bill as coming off in the early hours, but it corresponds with the Data usage as recorded by Dataman for the previous day.
Since I started turning off all the apps after use, my data usage is in line with what I've used since I first got the phone. I've had no "spikes" of massive usage. Maybe turning off apps after use is the answer?
I'm not saying its only facebook. I suspect there are several apps out there which do not control how their automated data updating works, and if, say, the wifi hesitates, or drops, it automatically goes to 3G download.
I know Mail Online (which seems to otherwise be a fine app) updates significantly to make your experience better - but I suspect the app is a bit out of control. There isn't an option in it to only update over wifi.
I'm sure there are other apps like it, as the mysterious data usage is across many users, and has been for a long time, and we still haven't been able to zero in on one specific app.
However, we all seem to have Apple (obviously) an O2, in common.
I too am having this problem with my IPad using GiffGaff which is piggybacking off O2
When I tether my iPad from my iPhone (vodafone) I don't use more than 4mb on my journeys to work, but as soon as I use the 3G from the sim card GiffGaff it seems to drain the crap out of it! 32mb the same journey time! (using the same apps give or take). To me this is a ISP issue and not a IOS issue.
I'm going to try and swap sim card/ISP to test my theory.
Ok so I changed the SIM card from giffgaff to vodafone and the rate at which the data goes down is exactly the same. So it's not the ISP, I now believe it's the iPad it self. Tomorrow I will test it thoroughly tethering it from the iPhone and check how much daa goes down from the iPhone to the iPad.
Same problem for me. This is what O2 just told me:
o2: I notice that a large amount of your data has been used at 00:00:00 hours. This only shows when any Internet related Application are running on your phone even after you've finished the session.When you access iTunes or any other Internet related app on your phone say radio, then the phone connects to the Internet and the Internet session starts. Once you're done using the Internet, you do exit the Application but in the background the App is still running. When the Application is still running even through you've exited the session, that's when your data gets used up.
You'll just need to switch off the phone and switch it on back every time after you've used the Internet. This will ensure that the previous session ends and a new session starts every time you access the Internet.
Now doesnt that sound like there is a problem at o2's end ?
I maintain its Apple's fault morally, but they don't have a liability. Based on my experience, and a lot of the above posts, there are apps out there which update, and download in the background in order to improve the functionality. Apple vet these apps. It seems that - say at midnight, if the wifi is inactive, it switches off or drops the connection (or perhaps the router disconnects). Then if the wifi isn't available at that moment it goes into 3G, and data.
I have proven it: I go to the trouble of only switching data on when I actively want it (how "Smart" is that ?), whereas my girlfriend can't be bothered with that so tends to switch on, and leave on. Then when bill time comes she's up at 500Mb+, whereas I am under 100Mb.
Now, we all have different wifi routers, and different apps, but... we all have the same iPhones. And, actually, it seems most of us are with O2, but its the Apple-supplied hardware (iphone) or vetted technology (apps) that is causing it. If Apple took the time to look at (I called them to report it originally as per my previous post, and - this is after all a forum hosted on their site !) I'm sure we'd have an answer - e.g. requiring apps to include an option to forbid background operating in 3G.
But - without any Apple input or acknowledgement, we are just wasting our time on this forum.
Folks, this was bothering me for ages as well. I gave up hope in O2 finding a solution and have turned to Giff Gaff as they offer a great deal with unlimited data (My data usage was still remaining higher than expected though).
However, when I was checking My iCloud settings recently I noticed that the default settings permits it to back up documents & data whilst on cellular data when wi-fi is not available. This will account for the data drainage during the night and when your iPhone is not in use.
This may be a long shot but I think that if you disable this, your usage may decrease significantly.
Go to Settings > iCloud > Documents & Data
and toggle the 'Use Cellular' to the Off position.
Let me know if that helps!