refusing to cancel their contract

mtn refuses to cancel their router after they want to charge me rediculous amount of money for prorata when their consultant emphasized on the actuall amount only for 5 times and no prorata was adviced even the agents on facebook take me from pillar to post just to cancel i was told to take it phumlani mall mtn store and the guy there refused to cancel and told me i need to call network services cause theres no coverage here yet the consultant called and said they have service not i must call a service i never heard of before its not even a month and they didnt debit when they were supposed to