MTN .. cancellations can't cancel an account.. wat a joke

I have cancelled my internet 5 months ago.. I've been sent from pillar to post consistently for these months.bi have done everything requested of me. And still 5 months later MTN is still debiting my account religiously. Each time I call in I'm told that my account is not cancelled even though MTN has my device and sim as requested. Even with the ref no I'm told to speak to various departments as even the cancellations Dept cannot assist. How is this fair.. take my money for a service I'm not using. But fail to pay and watch how quick ubr listed. I want my money back and this account cancelled pls.. I even asked for management at multiple points. I have yet to be called back. instead I have to keep calling and wasting my damn airtime just to put on hold or not helped .