Data depleted instantly after recharging! no help

on the 09/06/2015 I called Vodacom Customer Care as I have noticed that after recharging my account with data it will be consumed this has never happened in the past 7 years of being a Vodacom customer and furthermore while having the phone I have had for the past year, the consultant was transferred too in the data dept couldn't assist me in understanding how this is possible if I had no applications open or web browers open. she transferred me to her team Leader Wilson, while i waited patiently for 10mins on hold. Wilson also couldn't giving me sufficient reason and advised he would log a call with there technical dept. I have recharged my account twice and this problem has persisted. I recharge my data and straight after receive a text informing me my data has been depleted. Is it normally that I have recharged 4 times today and all occasions I receive a text right after informing me my data is depleted or no longer have airtime?<br> This is the most appalling service where the blame is shifted to the next person rather than thoroughly making sure there is no systems error etc.