Cancelling a Vodacom contract

Its impossible to cancel a contract, even after the two years has expired, Can anyone help me. I tried to change the open contract to top ip, I was told you cant. I then went to the shop to ask how much I owe, I was told R16087, which I paid in full. I was told my account is in legal they cant change to prepaid or to cancel my account. I must wait, I waited and called untill the 30th of the same month, I went to the shop where I was given a number to call. I spoke to the consultant who said I cant cancel, The supervisor is the one who said I can only cancel the contract if I pay R1300, She said that this Money was owing even on the day I paid the R16087, Why wasn't I told about this Money, she cant explain. As far as I.know I paid all the money I owe I want out of the contracts of Vodacom. The lady who helped me at Vodaworld is Maylener. Maybe she can tell me why she gave me a false amount. Thanks. I paid I want out.