FNB allowing **** and ***** to happen on my business account

Fnb is literally charging me for their own payment system and agreements with merchant, a few days ago I made a payment at wimpy for R293 where my account was on a positive balance and money was deducted off my account, this morning I get charged an excess honouring fee because they say wimpy didn't reserve the payment so fnb is charging me for that....how ridiculous is this....I am a customer, I pay the the bill, money leaves my account, and so because fnb and wimpy systems are not doing their job money is ****** from my account under the pretense of an Excess honouring fee...what kind of Micky mouse business is fnb running....what kind of **** is this that FNB is running?...I want my money back I don't care that is a small R-155, I will not sit by and let FNB **** me while I'm watching....and it's funny how that tansaction is not even accompanied by a notification