FNB frustrates clients

I was coerced into taking a revolving loan earlier this month. I used some of the money and to my utter annoyance I am told this morning that my account is in arrears because FNB decided to take the payment for the revolving loan on the 26th!!!!!! On top of this FNB has the audacity to charge me R40-00 because there were no funds in my account. I have been banking with FNB for over 12 years now. my money has NEVER been in on the 26th, for the last 8 years my money has always been paid in on the 28th or later. There is no option on internet banking to change the scheduled payment date, why do you give your clients access to certain functions but not others? Why can I not change the payment date on my internet banking? I want FNB to reverse the R40-00 penalty and change the payment date to the 28th