Mtn wont change my payment account after calling for 4 months

<p>The past 4 months I've been calling to change my account details. Every new month i get a message saying that insufficient account.</p> <p>I'm tired of calling your *********** unprofessional staff.</p> <p>This is *******.</p> <p>Hire professionals.</p> <p>Fix my account. </p> <p>I've literally called 10 times.</p> <p>Please stay away from MTN. Their service is pathetic !</p>