My phone (Xperia P running Jellybean 4.1.2) is consuming a lot of background data (about 70 MB in just 15 minutes) Since, I have a restricted usage of 2 GB, it's causing a great problem. I've already disabled auto sync, background data and other related stuff. Don't know the reason. Please help!
Are you rooted? If yes, then try Droidwall. Its an android firewall app which will give access to only those apps which you want thereby saving a lot of data. Hope this helps.