Won't cancel my contracts

I've been trying to cancel a contract for over 6 months with Vodacom... My calls and emails are ignored. When trying to call cancellations, the phone cut's off. When calling upgraded, my calls get answered and then when I ask for cancellations, they **** my calls. I have emailed CEO and MD - got a mail back saying my account will be investigated.... I mean how difficult is it? Still waiting for the investigation process... They will take you money and keep on taking it even when you try to cancel a contract. I'd say this is an unreliable network and service *****ing money from their clients!!