I am also a zong user form long time they were fair with therir policies but recently after reducing the rates they have started making users fool.
My Zong usb has recorded 4Gb and they are saying in message that you have used your 5Gb and i dont know how they are calculating data usage.
Their data theft policy has started this month and according to them i have used 35GB data whereas according to my calculations and data usage from device i have used only 28Gb data.
Last night I was out of data and ballance. I took loan and subscribe 100mb I was very careful to use it till day time. I just open few simple text pages and it was over and the thing is that zong device didnt recorded 100mb usage.