Horrible service and rude call centre agents

I took out a 24 months contract with MTN and it is ending today. Ive been trying to cancel it it for a month and a half now with no success. I call a month in advance as I'm under the impression that I need to inform of cancellation a month in advance. The call centre agent said she has cancelled it. Then two weeks back I decided to call and confirm and I received the most rude agents who said it was not and I should call today to cancel as the contract ends today. I call today, the agent tells me I should call tomorrow as the contract ends today, I can only cancel tomorrow. I ask since I use to receive data and minutes and payment was done from 14th till 14th and I'm paying in arears it means the 15 of June will be my last payment. This rude agent tells me no I will still receive data and minutes on the 14th of June and my last debit will be the 15th of July. This is unacceptable, my contract is ending today and I don't want to receive any more minutes and data on the 14th of June and my last payment to MTN should be the 15 June and we go our separate ways. MTN has rude call centre agents and they make it impossible to get out of a contract with them.