Contract Cancellation

Hi, I have been trying to call the cancellation department at Vodacom to cancel one of my contracts which is expiring on 10 April 2016. Everytime they put me through to cancellations, my call gets cut off before I can even speak to the consultant. I need to have this contract cancelled as I cannot afford nor do I need it anymore. I'm just afraid that if I do not cancel before 10 April 2016, Vodacom will extend the contract. Can somebody at Vodacom PLEASE do something and help me...!