Contract still not cancelled SIX weeks later

I submitted the original request to cancel my contract on 11/05/2015 as my contract expired on 10/05/2015, call ref ***. This was not done. I tweeted @MTNza and @MTNzaService on 26/05/2015 and 27/05/2015, I have still not received feedback on the cancellation. I then submitted a written request on 17 June 2015 and have still not heard back from MTN.<br> <br> Today, they had the audacity to send me an invoice billing me for JUNE. I then called the corporate office on *** on 25/06/2015. I asked to speak to the head of customer services. The receptionist was rude and put me on hold for over 40 minutes. I have now reported the matter to ICASA but I am still waiting for MTN to cancel my contract. I do not even want to be on prepaid after my experience with this service provider. They will never see another cent from me again.