FNB is the worst bank and best ***** ever. Changed banks due to this

FNB is by far the worst bank ever. I have been battling to close this account for a few weeks now. Recently I had made a purchase with my FNB account which resulted in my account going into a minus, I immediately transferred the amount from another account into the FNB account to ensure the account is in good standing which it was after I did the transfer. Today I see that i have been charged R110 for #ITEM PAID NO FUNDS 1 ITEMS ON 18/05/29. which I do not understand as my account had sufficient funds in for the purchase that was made. Please stop your thievery as you will be losing much more client's beside myself that recently switched banks. Please check my bank statement and reverse this ridiculous fee as this is *****ing.