FNB *****

I received #ITEMS Paid No Funds 1 lte MS 28/01/25. I do not understand this debit it all and I need FNB to refund this money and remove it. If there’s no money in my account why do you then deduct money that isn’t there then my account sits on a negative then you proceed to tell me you paid for the item and therefore I’m being charged because there was no money to pay for that item? Does that even make sense? So are you saying I can go to shops and start buying with a zero balance and my purchases will go through and sit on a negative and FNB would have paid for them? I want this matter resolved or else I’m canceling this card you will get that -R200 from hell