Cellular data drain (iOS 8.1.1) with "Documents & Sync"
I have been a loyal Apple customer for the past few years, but this iOS 8.1.1 is driving me crazy. I have 500Mb of mobile (cellular) data with my monthly plan. It used to be fine for me, now this is going in just TWO DAYS! After the new update the phone is eating data like crazy (not to mention the battery that goes with it). The main culprit seems to be "Documents & Sync" under "Systems Services". I have no idea of what exactly this is. I have "Use Mobile Data" toggled off at all possible places with no luck. The only way to prevent this is to actually switch off "Mobile Data", a pointless solution. I've tried to "Erase All Contents and Settings" as someone suggested in another forum, but after reinstalling my apps I have again the same problem. In "iCloud", I've turned "iCloud Drive" off, "Photos" off, "Backup" off, but my data keeps vanishing. Any help will be highly appreciated as at the moment this "smart" phone is driving me crazy.
iPhone 4S, iOS 8.1.1