Useless bunch of *******!!!

End of January, I called Vodacom to cancel a contract I had with them since they were not giving me what was promised. I was asked to call back after the 5th of February to do a premature cancellation, which I did on the 6th which was a Monday. I was asked to pay twice the amount of my installment, which I did and sent through pop along with other documents. The contract was then successfully cancelled. Fast forward to March 9th, I received a statement saying I owe Vodacom twice what used to be my installment. How??? If you knew my account was in areas, why and how did you go through with the cancellation? You now have no business being in my emails telling me about outstanding amounts, I cut ties with you. I am not going to pay anything, I have no obligation to do so, and I’m willing to fight this till the end!!!!