Wrongful bill

I received an sms from mtn saying that I should pay about 86 Rands otherwise my line will be disconnected. I wondered why because I paid mtn 200 Rands on the 31st of March. When I looked into my invoices I learners that my *** number which I canceled in January was not actually canceled but placed to month to month basis. I don't get why that happened when I specifically called and said cancel the contract and place it on prepaid. Now I don't care that mtn has been sending data and airtime to the number it is not my fault that the booza networks agent did not complete my cancelation. I cannot be held accountable for that. The agent must pay for it and mtn must refund my money. Likeafter so many contracts with mtn I would know better. Even your booza agents like they were no help Siphumelele, Nomfundo and Elvan. They all dropped my calls. Even with the reference number of the call for my cancelation there was no help instead one tried to persuade me to take a deal or whatever that she meant. I want a recording for the call I made to mtn proving that I did cancel my contract. And it is such a hustle to get a recording which they always say it's for quality purposes when let's see. I am angry and I am frustrated at such incompetence. I WILL NOT PAY FOR SOMETHING I DID NOT ASK. I WANT A FULL INVESTIGATION ON THIS WITHOUT MY NUMBER BEING DISCONNECTED. ALL MY NUMBERS. It's good to see that after all these years of being with mtn, mtn does not care about me but the money I pay. Reference number to the call I made in jan: ***. It shouldnt be that hard to find. Contact me on my direct number ***.