Contract cancelations

Been contacting mtn vangate since last week spoke to 2 different individuals. One advised my contract ends the 25th December the other said the 21st however I need to call 3 days before the 21st to cancel. Decided to call the 135 number as they always able to give more clarity and usually assist much better than store consultants. Man was i wrong I've been calling 135 for the last week and when someone answers im asked to hold and then the call gets dropped. Thought I'd then send an email to the retentions department to cancel and what do you know. You cannot email to cancel a contract. So if i cant get through and i cant do it in store and i cant send an email then how am I supposed to cancel my contract?