UNDUE DATA OVERCHARGES DUE TO INCORRECT CONTRACT

I logged a dispute with Vodacom on 19th December 2014 after receiving the invoice showing that I owe R10,308.78.<br> The agent who took my call on that day told me that the excessive data usage was based on an open contract i took on cell phone number ***. I told them I opted for a top up contract, mainly to get the iphone 5s, and explained to them that I don't have open contracts because i manage my usage and budget closely. On 11the January, i got a call from the accounts department and the lady who called me advised that Vodacom agreed to pass a CR note of R17082.94 which was 75% of the excess bill. She advised me to call *** to make arrangement to pay the bal. I called and the agent told me that because the CR note was not reflecting on my account then, i should call back on 20th Jan, only then can they see the full amount outstanding for which payment arrangement should be made. he said i shouldn't worry about paying until 2oth January 2015 when the credit note would have gone through. I am frustrated, and no one is willing to assist me to have this resolved. I have an overdue balance of more than R28,000 and a get automated threats of being listed.