FIXED INTEREST RATE BUT DEBIT ORDER AMOUNT INCREASED!!!!

I am on a fixed interest rate on my bond account and should not be affected by the recent interest rate hike but my debit order amount went up!!!!!!!! What is happening???? I have spoken to two of your consultants and they have confirmed what I am saying but no one is telling me why this is happening? And if it has been rectified ?I need answers URGENTLY!!!!