Temporary loan shark business

I recently found myself needing a small temporary loan to tide me over until month end. I usually only get paid on the 6th of the month. Well, I'd advise anyone wanting to use this facility to NEVER use it. I took out the loan on the 23rd, with the understanding that it's payable in 31days time. Yesterday, 7 days after taking out the loan, I had some funds deposited into my account. The temporary loan collections department took 99% of that deposit , to pay towards the loan, 7 Days after taking the loans. .this is called an activity based payment. I find this totally *********. It's left me with a negative balance as I had debit orders deducted this morning. I've been on the phone with FNB and they just refuse to assist, saying that these payments cannot be reversed. So until the 6th of the month I am completely broke and my bank account us in arrears. *********!!!!