Multichoice over deducting on debit order amounts

We signed up for the Black Friday special in 2018. This meant that our monthly premium would be R749 pm for 12 months, all inclusive. We added another Explora decoder for an extra R49 pm for 24 months. Our monthly premium should then be R798 until end Oct or Nov 2019. End of August 2019, the amount of R1,063 was debited from our account. We queried this (ref nr ***1/C1) and the call centre agent confirmed we were over charged and that someone will be in touch with us to discuss and confirm credit to our account. Nobody ever phone us and end of September 2019, the amount of R749 was deducted from our account. Deducting R50 less from our normal debit order amount does not rectify the R265 over-deduction. I downloaded the Multichoice app to be able to see our statements and saw that Multichoice have been billing us incorrectly since March 2019 and then over-deducted based on incorrect billing end of August 2019. Multichoice actually still owes us the balance of the over deduction of R265 minus the R50 they deducted less in September 2019. I checked the app again and it now shows that we are owing R997 but no statement is available to show how the hell they got to this amount. After subscribing for the price lock, we were disconnected a number of times for "non payment" but our account has never been in arrears. I felt this was in-excusable as we pay premium rate and expect to receive premium service. We've been Multichoice customers since 2003 and I've never experienced such incompetence