MTN - no response to cancellation of contract after 4 months of trying

I have been trying to cancel my MTN contract, which is at its term, and for the last 4 months and have not yet been assisted. None of my emails are answered. I am due for the upgrade, but since I have relocated to Zambia, I am un able to collect it, and my son is not allowed to collect on my behalf, hence the cancellation. What are my options? to continue to pay for a service I cannot use, or a new phone I cannot collect??? I think NOT! Are MTN not able to speak to their branch in Zambia, and assist me? Please can someone get back to me as soon as possible!