Poor service from DStv

I am exceptionally frustrated with DStv, they have to be one of the most *********** company's to deal with. I pay annually for my DStv in January every month, and am happy to do so as it gives you a free month. For some unknown reason last month they debited my account by R6410 (they did the same thing to me last year), although my account is up to date. It took me about 2 weeks for them to eventually credit my account. I spoke to countless agents and even a supervisor who assured me that he would sort my problem out, obviously he didn't as a full week later I was still not refunded. After finally getting refunded lo and behold it happens to me again this month. The problem is that they make out like it's my problem, I should contact my bank I must send emails and phone calls. It's very time consuming and extremely frustrating to deal with the call centre, my emails go unanswered. I doubt I will be renewing my DStv next year as their service is terrible. I can't understand how they can keep on debiting my account. What would happen if I had an emergency and was short of a few thousand Rand because DStv had debited my account unnecessarily?