Vodacom is trash

Vodacom are ****** of note. I wanted to cancel my contract with them and they offered me lower package which started on the 1st of October. I made double the payment so that I could be ahead and I was shocked when I received communication from the to say my account is in arrears. I contacted them to cancel this whole thing once and for all, and they told me that I have to pay the arrear amount of which I did just to cancel, when I call again they tell me the same story that they cannot cancel because my account is still in arrears, this time around they game me a new balance.