Bad customer service from Multichoice(Dstv)

For last 4 weeks I've been getting bad service from multichoice with regards to my account. My Dstv account has been cut off couple of times saying that I'm owing them money, to my surprise how can I owe you money if you debiting my account each and every month on the 20th. I phone 4 weeks ago to resolve this problem and they promise me that it has been resolved and won't happen again, 3 weeks ago same problem happen and even today my service has been cut off saying I'm owing an amount R688.70 while on the 20th of August they debited full amount of R549.