Bad Call center service-Data Disappearing

I bought airtime and converted it to one gig data promotion for R89 and my one gig got depleted within a day. I called the call center and spoke to an Agent whom couldnt assist and I asked t speak to the manager by the name of Matlhaku who was supposed to call me back and didnt call back.I called on a Friday morning on the 24-07-2015 and she told me that there was an active internet connection at night but she couldnt explain to which site i was connected to.I asked to find out what sites were visited by my phone as i was asleep at the time.She said she wasnt working on monday so she will get back to me today 28-07-2015 however that hasnt happened. I bought airtime again today 28-07-2015 and converted it to another one gig which depleted in less than 7hours without doing anything.I am really appalled by this kind of service and even thinking of actually canceling my contract with them.