Incorrect Billing after upgrading

Hello <br> <br> My complaint is with MTN accounts department and not with Hi store in Canal Walk in Cape Town.<br> <br> To cut a very long and ongoing story short, I upgraded at the End of September from a contract with a Blackberry handset for R209.00 a month to a Samsung Fame Lite for R168.99 a month. Paid the upgrade fee and handset fee involved, cancelled everything to do with BIS as it was no longer needed and walked away thinking my account would be debited correctly every month. <br> <br> October was charged R421.76, November charged R204.00, December charged R244.00, same for January and now will be charged the same for February! When I called for the final time trying to sort this out I was told I need to send through my contract as the billing amount is incorrect. I am currently in the process of moving and my contract is in a box in storage. When I asked the store they told me \MTN does not allow us to keep your contract so we shred it"! That is a complete violation of the Consumer protection act and is inexcusable! I have a print out from the shop that accessed my account showing the billing says R168.99 on the system yet I am charged different amounts every month. <br> <br> Please I need your help"""