Unexplainable diminishing airtime balance

I am disappointed at the high charges or rather ********** acts by this network every time my mobile data is turned on. I have been a victim of airtime theft before but when I enquired I was told that it would be due to my applications software updates settings. Last week I recharged my airtime twice, all was normal up until the amount reached a balance of R48.00 hours later having used the internet for a few minutes (without downloading material) the balance declined severely to an amount of R14 which later ended up as R3,40 the next day. I did not bother lodging a complaint with them due to past experiences with the consultants’ poor services. I ask that they make a proper investigation regarding this before giving me false reports regarding my pecu**** diminishing airtime balance. This is highly unacceptable!