DEBIT ORDER GO OFF 3 DAYS AFTER STATEMENT RECEIVED

On my online banking, they allow you to modify the debit order date, I thought I would move it later as I had just got new tenants in my property and did not know when funds would be available, to my dismay, they have changed the debit order to the current month, meaning for this month I have paid the account twice and it's my salary date which is utilised for my 2 bonds to come off, I then rely on the rental income to pay my accounts. I call the call centre and a very rude man just tells me that I did it and it's my problem now, like how rude and uncaring can a person be???? This is not on Discovery, if this is how you treat people, I will pay off the credit card and change my medical aid to Bonitas.