Just Cancel my Contact like I asked

<p>I have asked MTN time and again to convert my account to prepaid and send me confirmation of this via email but they KEEP debiting my account. </p> <p> </p> <p>When i phoned through months ago the agent told me point blank that I can't set this up in advance of my contract expiring because they will just ignore it. </p> <p> </p> <p>Stop taking money from my account. I don't even use this SIM card. </p>