MTN charging me for itemised report I cancelled even though I don't receive it.

For over a year I have been requesting MTN to cancel my itemised calls report. I follow the correct procedures on the and I get assured by the MTN employee that it has been cancelled. I've done this 3 times. Yet years later I am still being charged for it. This in spite of not even have received the report for over a year. So now they don't send it to me but still charge me for it.