MTN has no customer service

I recently decided I no longer need my MTN sim card to be on a contract deal. I went to the store to cancel my already overdue contract but was told this could only be done telephonically. After multiple e-mails as well as hanging on to calls for more than 30 minutes on average, nearly a month later I have had NO feedback from MTN. I stopped the debit order upon which the only automated message I received was that they were cutting my sim card unless I pay the overdue amount. ZERO customer service. I will not be staying with MTN