Very bad service in cancellation department

I phoned Vodacom twice to cancel my one wifi number ending ....980 and they said it is cancelled.. well this month I get another statement with this wifi on.. I phoned in time to cancel this contract but clearly the Cancellation department does not cancel this or don't know what they are doing... This is not exceptable anymore as this happened with previous contracts I cancelled as well... Vodacom is going backwards or cancellation department is too lazy to do their job.. Think I must cancel my debit order and pay Vodacom myself for the one wifi then the money can't go off for the other one.. this really makes me mad.. I sent them email and they dont even bother to come back... Very very bad service