Ridiculous bank charges

FNB is on a serious mission to ***** our money as I was charged R375.00 with reference #ITEM PAID NO FUNDS 3 ITEMS ON 20/01/20 which I refuse to pay. This is not the first time that such ridiculous charges are on my account. There was more than enough funds in my account when the transaction went through hence the transactions were approved at the merchant\s otherwise, the system should have declined. We I opened an account at FNB, I wanted banking services, not a IT course on how your system works in the background and I think all your customers opened their account for that sole purpose. How long the merchant takes to present the voucher, is non of my business but a business between FNB and the merchant. I can live with your high service fees but I cannot allow you to ***** my children's money and I want that charges to be reversed or I'm moving my account back to ABSA or open a new account at Capitec. I'm sick and tired of this abuse, I can't take it anymore.