Incorrect Debit dates

So Telkom the biggest ********** in SA, I have 2 mobile routers 1 is on a month to month and the other is still on contract. My bill monthly is R238.00, I had changed my bank account details and debit date for the 25th of every month, keep in mind my account was up to date. Telkom takes it upon themselves to debit my account on the 16/11, 20/11 and the 26/11. Every time they debit my account the bank charges R147 per miss debit. Now who becomes responsible for this as Telkom debited me on dates that they were not supposed to.

Need an urgent response to this.