High charges

I have a business account with fnb since 2009 with a turn over not less than 1,5million, lately I requested increase on current overdraft I was denied instead they started to reduce, they paid debit orders that exceeded my the limit and they are charging R700 and above for that today they charged again R1400 again I'm fed up with this ******* , .'' How can we help you'' I'm doubting that in my experience with this institution.