Over-charged call rates

Hi there, on three occasions now you have charged me about R5 per minute for a call to Angola, instead of the 99c as advertised on your website. I have called customer care on all three occasions, once getting someone spewing nonsense like calls are billed per second, not per minute, which was irrelevant as the call still comes to R5 per minute, and not 99c. Herewith a reference number, you owe me money and I want it refunded - ***.