FNB debited my account causing me to have unpaid charges

My salary date is on the 27th and FNB deducted from my account prior to that . I had informed them that my salary date is on the 27th and that all charges should be deducted on that date. to my surprise I have charges of unpaid fees which I am not at fault for. when I asked the consultant from the banking chat by the name of Nomaswazi to reverse them she gave me all sorts of stories. To a point that I had to remind her that my salary is on the 27th and so are all my debit orders. The personal loan I took with them I did inform them that it should be deducted in the 27th and there for I refused that pay charges that are not my fault. they can even go back to their records and listen to that call I had when I was taking that personal loan. Nomaswazi the lady that I was speaking to was not helpful at all in fact she came up with so many reasons as to why she will not reverse the funds after I had given her all the fact. I want those charges to be reversed