Promises not kept by mtn

I have been trying to cancel my contract with mtn since February. It ended on 29 April but the mtn consultants told me I should phone a month in advance. I phoned on the 25th of March and ended the conversation with the man saying it's canceled and that my last payment is in April. On the 21st of April I got an sms saying that I am going onto moth to moth for R1200. I phoned them and they told me my contract isn't canceled and if they cancel I will pay in May too...

After numerous phone calls and plenty time on hold it was finally canceled on Friday 23rd of April but I have still not received a phone call from Mtn as promised numerous times. The statement still says I pay in May which according to my phone call on 25 March is not fair on my side. I phone and spend hours on hold and get through to nobody. Terrible service mtn