Overcharged For DSTV Subscription

I'm currently subscribed to DSTV Compact and added Showmax and I usually pay R458 pm for this subscription.This month DSTV billed me incorrectly and debited R876. I have called DSTV numerous times and inboxed them in their Twitter account, however, I keep receiving the same answer that they're investigating the matter or the matter was escalated. DSTV absolutely doesn't have respect or value of it's customers. DSTV has zero customer satisfaction and very quick to disconnect their services if not paid and yet have the audacity to overcharge us! I'm canceling this wack services ?.