No reply from Call Centre

I went into a MTN shop and requested to cancel my contract and was told I had to call 808 to do so as they can't assist. I called 808 to be told by the recording that there is a delay in responding to calls. Well holding on for ages there just isn't a delay there is no answer. How does one get hold of anybody at MTN to cancel a contract if they don't answer their phones. I have tried this on numerous occasions at different times of the day and the weekend for the last five days to no avail. <br> Does one need to resort to stopping a debit order to get a response and stand the chance of being blacklisted.<br>