FNB Bank-quick money making scheme

I have borrowed R9000 from FNB bank to be able to process my debit orders by month end. I did not even had the R9000 in my account for a week before FNB took R10 000 out of my account. After a complaint they reversed the transaction, just to repeat the process the following day. The loan didn't serve its purpose. I was unable to process my debits with the temporary loan's money, since it was only 9 days in my account. FNB Bank took back their money with a R1000 interest before my debits went through. They told my they are authorised to take that action according to the loan's stated policy and refused to assist me further. FNB have thus invented a quick money making scheme via a temporary loan they offer. They lend the money to me for 9 days and made an entire R1000 out of this scheme