Cancelled contract December 2017 today is 17 Aug 2018 and debit order still going off. CANCEL!!

I had a 2 year LTE wifi contract. my two years expired and I did not renew my contract. I have tried cancelling this since December 2017 as I am STILL being charged monthly. I have called and emailed Telkom and no help. Still today a debot order goes off my account for wifi I don't need as I now have fibre. I want this account cancelled and my paments since December 2017 returned. I am tired of holding on their call centre for hours and STILL they don't cancel that contract but deduct every month. This is theft! Telkom cancel my contract TODAY!!