Item paid no funds

Hi please assist me get my money back. I am an FNB cheque account holder and in the 20 February 2020 I was charged R125.00 for "ITEM PAID NO1 ITEMS on" FUNDS This charge 'Items paid no funds' is supposedly because they honor a transaction I made when I had no funds. However I had funds in my account. This is day light ******* and want my money back. Now I have a negative balance of -R505.21 because of charge.