I want to cut ties with FNB

I am so frustrated and upset with FNB's service right now.

Yesterday I had a R315 in my account, a debit order was set to go off and couldn't because of insuffiecient funds.. However now, I have an outstanding balance of R750 and some odds!!!!! There was fees pending since monday that also went off, and I dont get how this happens. As an example: I made a online purchase on monday, I got a sms saying money went off my account, I checked my balance which also showed me the money was taken and then today the same amount gets deducted, adding to this outstanding balance.

This issue with fnb has affected my life in such a horrible negative way, because I spend more money on fees than anything else and I cannot handle it anymore. I am a single mother of two, I work hard... The R315 that was in my account was the last bit of money I had left to make ends meat... Now I have R1000 coming in to my account and I have a outstanding balance if R750. So this means my son's school fees cant be paid, I go into arrears there, and he won't have transport for the rest of the month!! I want this fees recalculated, and you people need to sort out your **** and systems because you have no idea how you are ***ing with someone's life and the stress you are putting them in!!