DATA BUNDLE

I have got a serious proble with MTN SA. I switch off my data bundles every night before I go to bed. But atleast twice a week my data bundles disappears and whenever I call MTN it takes me at least 12 hours to get hold of them, simply because their lines are busy. I bought weekly bundles on saturday 24 May 2015 and my data bundle dissappeared on monday 25 May 2015 and when I tried calling MTN and I was finally able to get hold of MTN tuesday 26 April at 09:29am and they telling me that its applications that finishes my data. my question is how do applications finsish ones data if the mobile data is turned off/ when simcard is inserted in a phone without internet. I spoke to their consulatant this morning (ZAMA NGCOBO) and she showed no interest in listening to my side of the storry!!!