Refused to cancel a contract after 1 week of usage

I am being refused to cancel a contract where my device was recalled and I am without a device since 23th of January. I only used a device for 7 days then it crashed and when I wanted to cancel the contract I was told by staff that I cannot and I need to pay for the rest of the months. I am being refused the contacts of the store manager, wrote the email to head office but no one is willing to help. My worry is that all of these is dove verbally and there is no traceability of emails as I am not allowed to contact staff by email. CAN I HAVE MTN REPRESENTATIVES RESOLVE THIS ASAP. As a client I have the right to cancel my contract if I am not happy and to have my complain attended to. IS THAT TOO MUCH TO ASK MTN??????