Lack of Business Ethics

I tried paying for my DSTV account online on the 3rd of November and the transaction was said to have failed. I thereafter paid for my account at my local Checkers store. On the 4th, the online payment went through. Which meant that I had twice paid for my dstv subscription. After fighting with them for more than 10 days to get my refund (1 of the 2 payments), they finally gave me back my refund. However, when I checked my amount to pay for December, it's double my subscription rate of R874. Why is this? I paid twice this month, which is why I asked for the refund. So why do I need to pay double now for December?