DSTV incorrect debit order amount deduction - no explanation and incorrect offset

I am on the price lock price plan of R899.00 per month from March this year. The billing via debit order has systematically debited on the 01st of every month until 01 September where an amount of R1,004 was debited from my account. I called +***2 on the 03rd September where I was assisted by two representatives in the accounts department. They acknowledged my queries re the deduction and said that all debit order instructions were wrongfully debited. My question then was if a debit order is set to a specific amount, how and who can change it to debit order without the consent or notifying the account owner, but that fell away after they acknowledged the incorrect debit of DSTV customers via debit order. They provided me with a reference and said that I will be contacted to resolve the issue and that the difference between Sept and Oct debit will be offset, it's the 30th Sept and no one is getting back to me, even after numerous calls.

I checked my statement and they have only offset R74.00 against my October debit order instead of R105 with no explanation. i.e my debit for October should be 794.00 and not 899.00

Best someone gets back to me with the explanation and correct debit for October as if this is going to be prolonged I will cancel my debit order with DStv and continue paying them via Eft on a monthly basis as my control is better than theirs.

I have never made ANY late payments to Multichoice and then when this happens with my money they don't even send a letter out to their customers apologizing re this, I have to follow up with queries and still await feedback. Disgusting service