When will FNB stop taking money from poor people? God Help!!! Is there consumer protection act that works???

Im sitting with a personal account heavily in overdraft due to a bunch of #Excess item fees and and bunch 8.50 debited every time some service was trying to charge my virtual card although i blocked the card i incurred over 30x 8.50 charges over December and Jan but this morning I am furious that yesterday I had R36 in my business account and made a purchase of exactly R36 and the available balance was R0 (zero). This morning I receive payment of R500 from a client and my balance is R345 because FNB has charged my -R155 #Excess Item fee on a purchase that was made last week Friday!!! How the hell do you explain such a thing??? I made a purchase on Friday with sufficient balance in my account and 4 days later I have R0 in my balance you charge me a penalty to say that I didnt have money for that purchase? It's utter nonsense they cannot explain this fee how can the consumer protection not help us from this it's killing us times are hard we can't afford to have the bank do as they please with our money!!! It is simple Maths if I had R10 left in my bank I wouldnt have been charged this #Excess fee but the moment you reach R0 or below somehow they charge you for things you PAID for days prior it is sick. Can any suggest where else can one take this complain further this is a crime against struggling people that entrust their money to a bank that promises so much and makes us miserable!!!