CONTRACT NOT CANCELLED

Advised by MTN during month of April that I could only cancel my contact as of the 23rd May and would need to call back after this date to convert to pre-paid. It is now 10th June and my contract has still not been cancelled. Best part is that no one is able to contact them as apparently their services have been disrupted (for weeks now)?? Strike perhaps... heard so many stories already, waited a total of 47 minutes during one of my calls for no answer.. not to mention that I have a credit limit on my contract however now that I mention cancellation then suddenly my bill is much more- Why???. Please I would just like to have this sorted - want to be rid of MTN for good.. worst service provider that I have ever dealt with.. ever! Have also sent numerous mails and complaints with no feedback or response.