Same billing error 3 months in a row

Had a Dualview decoder, gave problems and when I took it in was told they will replace it with 2 decoders. The 2 decoders was then loaded as 2 separate packages and I was billed accordingly(R1700). I phoned in to query the high debit order and was told that it was an error on their side and to reverse it and make a direct deposit (R1098). The same happened January and from then on, my service has been disconnected weekly, with me phoning in weekly and explaining. I'm then promised that it will be corrected and that the 2 accounts that has been loaded by accident will be deleted and corrected. I speak to a manager weekly, explaining, going through the whole story for them to apologise, connect my service and promise that it's now fixed, only to be repeated a couple of days later. I have spent almost an hour on the phone with Multichoice in the past 3 weeks. What do I have to do to get this matter resolved once and for all?