Cancellation request lost in the system

I have tried to cancel a service since October 2020. I have called 4 times now and each time I am told that it will be cancelled within 24 hours, but at the end of the month I am charged for it. I have asked that I be reimbursed for these past months as I made it very clear that I no longer require the service, but because these companies can stick their hands directly into our bank accounts I have no way of stopping the payment without negatively affecting the other services that I am still interested in utilising. Each time I call they say a manager will call me back, I am yet to receive any kind of feedback from Vodacom. Why must a customer throw a tantrum before they are heard and receive proper service?