Unauthorised upgrade

Upgrade fee was deducted from my account in May without my concern and when I informed Vodacom that I am changing back to prepaid I was told that I am owing R210 because I have upgraded my contract. I told them that I have no idea of that but nothing has been done until today. this happened inJuly already and I have been sent to different departments without any constructive response. instead there is no update on progress and I am now tired of following up since August I am getting the same response.

All I want is Vodacom to refund my money and correct the error that I am owing them because I cannot manage to have my name blacklisted for something that I am not responsible for. please can someone take responsibility and resolve this irritating issue.