CAN'T CANCEL CONTRACT ON DATE SPECIFIED

My contract which I have had with Vodacom for MANY years was due to be upgrade for which I traveled all the way to Vodaworld in Midrand on the 10th January 2016. Just to sit heavily pregnant with a bored toddler for longer than an hour - I asked for an upgrade, I updated my details (email address and surname), and was sent off without my new phone or contract being told it would be sent via courier early the next week, as they had \upgraded their systems\" and this was causing a delay. Needless to say no courier arrived and not even a phone call received with an explanation. Two weeks after I called in to cancel just to hear its not even reflecting on the system. I asked to cancel my contract which I was advised to do by 1 April 2016. I spent around 80min on the phone in total calling the cancellation department as well as the customer query number to cancel, I can't be transferred to cancellations as their 'number is not working' and someone will call me back. No one has. I have sent TWO emails to their contact center (31/03/2016 and 06/04/2016) for which I got automated responses that I would be called in 24 hours. I haven't. I think they are useless to say the least."