MTN's Customer Retention Department is **********ly ***********

I have been attampting to cancel a monthly debit order by MTN on my bank account now for over 9 MONTHS. This is from a contract which I cancelled with them last year. Each time I attempt to do this through their call centre, I am transferred to 'Customer Retention', where I am put on hold for over 45min! Eventually getting through I am given a 'Reference Number' and told it will be dealt with. IT HAS NOT YET BEEN DEALT WITH!!!! COME ON PEOPLE!!!