Awaiting cancellation for over 6 months

I app****, in store, in April 2017 to have my telkom landline and adsl cancelled as I moved house. To date, I am still awaiting the cancellation. I get billed every month. I visited the same store on the 24th of September 2017 and they assured me that I will receive feedback and will be paid back the amounts incorrectly billed. I am still awaiting this feedback. This is unacceptable service.