Debit order woes

I have been asking MTN for the past 4 months to update my debit order date to the 1st of every month and not the 20th as it currently is, and I did it in store as well as utilising the call centre. I was told it was updated and once again it went off tonight, and as an added surprise an extra R1000 was added to the bill. I immediately phoned the call centre to query the transaction and was told the change was not yet active as it takes 40 days (40 days from when??? The middle of 2020?) And the answer to the extra R1000 was that they did not deduct the money last month and I was supposed to be informed that it did not happen, but suprise surprise, I was not informed. In my mind, the lack of debit order on the 20th signalled that the change was activated, but today I found out that once again that the great service of MTN lacks. I am upgrading in less than a month, I am seriously contemplating cancelling my contracts (I have more than1) and moving to another provider.