Vodacom useless

I lodged a complaint at Vodacom stating that they had canceled the auto purchase of data, this after I reported it in Hello Peter. I was subsequently called by a vodacom agent and was advised that the auto purchase had been canceled and that they were giving me a refund. I appreciate this, yet I have just received another notification that data was low and the auto purchase would take place! The cancelation has obviously not taken effect? How much longer can this go on? It's thoroughly disgusting. They don't seem to know what they are doing apart from milking me as a client. What more can I do. I went to the head office and they could not help.