No Service

I had an account with MTN for several years for an internet ****le. For well over a year, the ****le failed to connect to the internet. The internet store said it was out of date and needed to be updated. I chose rather to cancel the service. I've been trying since then (over a year) through numerous emails & telephone calls to request cancellation. MTN continues to debit my bank account every month for a service that I have not received for over a year. They refuse to even respond to my emails.