Refunded but still being billed fot the same thing

On the 13th March I logged a complaint on this very site. Someone from Vodacom called me, apologised profusely, promised to have the matter resolved and issue a refund as I was being incorrectly billed. I did receive said refund. Howeve 2 months done the line I sit with the same problem! I do not even receive my statements anymore. I ask for them to be sent to me and again I am being charged for exactly what I was refunded for prior! I spent 31 minutes on a call to customer service only to have a manager tell me that it is a technical error! A technical error Vodacom has been experiencing for the last 5 months! I have subsequently cancelled 4 of my 5 contracts and sadly Vodacom has lost me as a customer all together....