Debit order change with Wesbank

I have a car finance with Wesbank and the debit order for this was the same date as my salary payment date 26 of every month. I recently changed jobs and my salary payment date has changed to the last date of the month. I would like to update this debit order date as it may get debited with not enough funds left in my account. I have been trying to get this date changed with no luck so far only to be told that i can not change my debit order i can only change it in august but this will affect my credit record. The consultant told me that there is nothing that can be done except to wait till August but on the other hand i will be charged penalties everytime my debit order bounces. This is so unfair and why does it take six months to change or update your debit order, life is unpredictable, one should be able to update anytime. I also asked the consultant to assist with a payment arrangement and she said she can only assist when my debit order bounces, it doesnt make sense.