No response for cancellation

I want to cancel my MTN data contract. I have phoned the cancellation number, but cannot get through to a consultant. On 6 September I emailed customer care to find out how to cancel the contract as I can't get through when phoning. I was advised to email ********** and that I need to give 30 days notice. I emailed retentions on 7 September requesting a cancellation, my last debit order date and saying I am giving 30 days notice, I received an email saying I would receive feedback within 2 business days. When I didn't receive feedback I forwarded the email again on 13 September but still no feedback. So no one is answering calls at the call centre and also no replies on emails?? I want my contract cancelled an consider 7 September as my 30 days notice.