Bad customer service and arrogant call center agents.

At the end of September Vodacom double deducted monthly payments, I phone to log a complaint and they promised to refund me instead I didn't. When I followed up my complaint with out any feedback from them. They told me they credit my my for next month payment which is more than my monthly payment. Even day my refund is not paid as yet. After instruction me to send bank statement as proof of payment nothing happens. I will wait for my contract to expire then leave their bad service for good.