Disgusting Theifs!

At the end of March 2015, I went into the Virgin Mobile store in Clear Water mall. I asked the consultant how much I had owed on my account as I wanted to pay everything that I owed for that month whilst I still had the money to do so.. He gave me the total amount of R780. I had asked him if my debit order is still going to go off once I pay this and he assured me that it wont as he will make a note on his computer. I paid that R780 via Easy pay. Two days later the debit order went off for another R780 from Virgin Mobile. I called the call centre and I had spoken to about 4 different people explaining my story, each one of them assuring me that I would receive my refund after the Easter weekend. After the long weekend I still hadn't received my money so I called yet again, and spoke to a consultant named Susan. She informed me that they had taken that extra money that they debited from me and put it towards my bill for next month. Although i did not authorise such a thing, they had already closed my invoice. I was then due a refund of R400 which was promised to be refunded to me by the 9th of April, which to this day i haven't received! please give me back my money!!