Reversal fees dispute

Good day... I just chatted to a banker in the fnb app and explained that I would like to dispute refuse charges on my cheque account... She them advised I call ***...which I did but I somehow get a operator to assist me who doesn't understand my query. This is frustrating.

I am currently on unpaid maternity and managed to hold off most of my debit orders.. However some were stil deducted and fnb now charged a total of R800 and something for reversal placing my account in a overdraft of 2000. I would like fnb to dispute these reversal fees or at least provide me with a discount as I've been a client for years and this is the first time I'm in this position.