Vodacom Pathetic service

So I had two contracts with Vodacom, last month I requested a settlement amount for one contract so I could close it, 28th of Jan I went to the nearest Vodacom shop and I paid the settlement amount that I was told to pay and sent through my proof of payments as well as my ID copy. Than my bill came in Feb only to find out I have billed twice the same amount that I had already paid, for the contract I had settled and paid off. From the 6th of Feb I have been calling Vodacom several times and no one seems to know how to do their job in Vodacom because several disputes have been logged but only to find out the were never resolved because they were logged to the wrong department. 1st of March my debit goes through and that means I will be billed an incorrect amount. I will make sure Vodacom does not take any cent in my account until my issue has been resolved because I will not pay double amount. What really annoys me is after making hundred calls and no one and I mean no one was able to assist me but instead I was sent from department to department and many disputes were logged to wrong departments. I'm tired of calling and explaining my issue to your useless employees who don't know how to do their job. My last reference number for my query was 1- ********** ********** . Can I get someone to resolve this issue ASAP or else I will move to a different provider and already I have stopped using all your numbers. How can a simply query be so hard to resolve?