Lost data and inaccurate account

During the time period that Vodacom had a "glitch" and all the data was lost, they took 300 MB of my data and charged me an extra R1502 for out of bundle data used within a time period of 2 minutes while my phone was on wifi and all my data was off except Whatsapp. When I made an enquiry about it they just said that I did use that data and that the "glitch" only affected pre-paid and top up customers. They said that we have to pay and there is nothing they can do. This just shows me that they do not have their clients best interest at heart and does not want to help. I do not appreciate being **** to and schemed out of money. Worst service I have ever received.