Cant stop packet data in my android phone
I was having the same problem, had mobile data off and still it kept on charging 4 paisa now and then. Eventually I seem to have resolved the issue by checking "restrict background data" in advanced settings of mobile data.

EDIT

I figured out that in my case the location was enabled which was accessing mobile data. To see what is causing your data to leak, you can install mobiwol from play store and it would display the applications which are accessing mobile data and wifi.