TELKOM refuses to rectify their error

I am an old Telkom customer and experienced such excellent service that I recommended many new customers for Telkom, BUT all of a sudden they made a mistake with my Debit order and now penalize me for their mistake. In vain I phoned and visited Telkom the past 2 months to rectify the problem, but with no avail. Here my latest correspondence to Telkom re my WiFi contract amount after I again received a bill for the wrong amount to be paid on 5 July 2023.: Dear Telkom, I gave instructions that the Debit order must be deducted on the 5th of each month. I visited, during April 2023, 3x afterwards Telkom Cresta to make sure there is no error. They confirmed during each visit all is in order, that Telkom would deduct the R209 end April from Nedbank and then afterwards from Bidvest Bank. Telkom Accounts Dept made a mistake and tried Bidvest end April in stead of the 5th, also they did not put the Debit order to Nedbank as arranged. Why must I be penalized for Telkom's mistake? I only owe you R209 and nothing more.