despite requests in writing to stop still billed !

i called MTN in January and February . i have reference numbers. since then not able to get through to anyone on the phone so have emailed my requests in march and April . I have reference numbers \ we will get back to you in 5 working days"but no response or action<br> My contract expired at the end of January . i want to carry on with the same number and top up but stop paying for the handset . I have requested this . I am still being billed in full. I cannot speak to anyone . no-one ever answers the phone. the Hyde park branch say they have the same problem and Paul told me that i need not worrry MTN will automatically stop billing me for the handset. However i have requested this in writing as well to be sure there is No mis communication <br> MTN - this is unacceptable<br> """