Vodacom refusing to cancel contract

Again, I have tried cancelling another one of my cell contracts on Vodacom ,"old system" and Vodacom refuse to get it right. Mobile number *** was ****** in April 2019,I did not replace,but was billed until the cancellation time in July or August. I tried to cancel before but was advised to see the contract to end as I would lose the airtime,which I did not use in anyway. I did this. I called to cancel in July and August and believed it was done. When I called perhaps a month ago I discovered that it was not cancelled, I cancelled again and asked for my refund. I was told it was cancelled and would get a refund to my account in five days,but would be contacted. The contract was not cancelled,I was not called. Can someone please attend to this,it seems the only time someone does anything only when a customer reports it on social media.