Telkom Mobile is not cancelling contract

I have a 10G + 10G internet contract which expired on 31 January 2015. I completed a form at the Telkom office in Nelson mandela Drive that the contract should be cancelled at the end of January 2015. This was never done. I then contacted their call centre and spoke to Naledi Mjwara who gave me a ref nr ***8. This reference number was for the cancelation of the internet contract and the BIS subscription. She ensured me that the internet contract will be cancelled and the R 299.00 that was deducted for February 2015 will be credited to my account. I received another account for March 2015 in which Telkom Mobile still shows that I have to pay another R 299.00 for March 2015. So I went on their internet site and raised my problem again. Someone from Telkom Mobile responded in requesting my ID number. I received a sms on 4 March saying that my call nr ***8 has been attended to. When I contacted them, they confirmed that only the BIS has been cancelled and again the contract is still not cancelled. So I have requested Telkom Mobile in many different ways and on many different occasssions to cancel my contract and still, R 600-00 later it is still not done!!!!