Vodacom Continous billing after requesting for the cancelation of contract

My name is Thobeka Zulu. I have a problem. Vodacom did not cancel my contract after calling them and settled my account. The laidy **** and said she will send a notice to her bosses and august will be my last month of paying but after that, they still billing. Today they billed my last cent:R720. My account no:I***. I am very disappointed by vodacom and this thing has started affecting my credit score. To think that we really working hard in this economy, and we still have cases like this. Please help.