Early debit order

I have an agreement with African Bank that my debit order with them would be collected on the 25th of every month. This month my installment was collected on the 22nd. The funds available in my account were put there for me to purchase flight tickets so that I could return home. As a result of African Banks failure to abide by the agreed debit date, I will not be able to return home this weekend. After contacting African Bank I was told there is nothing they can do. I also contact my bank to reverse the debit and was informed that this is not possible. It is completely unacceptable that African Bank feels that they can collect whenever they please. I expect somebody to contact me before the end of the day to resolve this and also have the money returned to my account before close of business today.