Item paid for no fund ****

It's damn unfair that I'm charged item not paid for not having money in my account,it is obvious that I am already struggling with paying the monthly account fee on time, however it is always paid. To be charged a bank fee, and at the same breath charged for being unable to pay it on time is day light ******* and it's not the first time. I feel the only solution is to shut my accounts with FNB, together with my children's and advice my friends and family to do the same.