MTN - Making it impossible to cancel contract

My contract with Mtn has expired(over 24 months) and I wish to cancel the contract with immediate effect but Mtn has now purposefully made it nearly impossible to cancel the contract as it can no longer be done over the counter at a Mtn Retail shop. You are basically told to dial 808 which I have tried for long periods and it is simply impossible to get through and that is exactly what Mtn wants. In my eyes it is ********** and will drive customers like me away for good to take my business somewhere else. I have now send an email to customer care in hope to get a response regarding the cancellation of the contract. Please provide a solution to the above problem or I will take steps to cancel the debit order with the bank so Mtn don't steel any more money from me which is clearly Mtn's intention...