Excessive Charges

I have run a business account with FNB now for many years, in March I was in the unfortunate position to go over my limit to the tune of R 200 because a payment that I was expected arrived 2 days later than expected. The bank levied my account with penalty charges to the value of R 770....!!!!! This is excessive considering the value of the amount overdrawn, but when I approached the branch, I was told that it is system generated and there is NOTHING they can do to help. This is why the bank makes the money it does clearly, I think its time to consider moving my business account to a bank that takes its clients' interests a bit more to heart...Sad but what choice do I have???