OR Tambo Parking Overcharge

I accidentally parked in the long term parking for 2,5 hours and was charged R540.00. When I phoned in to see if the charge could be remedied the staff were unhelpful, eventually offered to put me through to the client services manager and then cut me off. All I want to know is if the matter can be resolved because it is an easy mistake to make going in to the incorrect parking. I am fro out of town and was not aware of long term parking issues.