Still being charged for cancelled contract

I have dealt with Zandile, Thumi and Nonhlanhla on the 20/09/2017. I noticed that I am still being charged for a service which I cancelled in January. I was told that an agent will call me back within 7 working days to arrange a refund. Today 10/11/2017 I called again and spoke to Thabile who referred me to customer care solutions department. Tatum answered the call and half way through the call ended and went to the survey. I call again and the same thing happened with another agent. The third time the agent asked me to hold on, 30 minutes later she still had not returned. I don't appreciate this kind of service. I have been with Vodacom for 14 years but am strongly considering moving my business elsewhere, WHO can assist me with my refund??