Disappearing airtime and data and no refunds after a complaint has been lodged.

For the past two weeks I have uploaded almost R1000 airtime on my contract and used it to purchase data yet it keeps on disappearing. I've contacted Vodacom countless of times about this yet they have failed to assist me giving me false promises of getting back to me. To top it off today is the 1st and my airtime that was " loaded " as per contract doesn't even appear, around 1am when I checked I had no airtime and no data yet I'd purchased 1gig and had airtime but the airtime uploaded according to them they claim it's internet usage whilst I'm a student therefore actually have wifi and that they will investigate the matter and get back to me but they never do, causing me to keep following them. The last phonecall I made I felt completely disrespected by their team leader/supervisor