Point taken Business - but is it unreasonable to expect customers who are worried about the cost of parking overall to take into account that there are other customers to be served as well (maybe before them)? 

It's unfortunate it happened to you - maybe they should have a system like they do in the airport in my hometown (and in Muscat) - where you pay your parking at a machine before you get in your car, and you have to exit within a certain number of minutes (you feed another machine at the exit to the carpark with your receipt from the first machine)