ACSA heartless

I'm very upset with the lack of understanding received from ACSA. I made a mistake and explained myself, but there's no mercy for me. On the 13th of January I visited the O.R Tambo airport. Not being a frequent visitor to the airport or the parkade ,I mistakenly parked in the long stay parkade. Please note I stayed for an hour and a half,seeing a loved on off at the airport. When I got to the ticket machine I saw my worst fears were confirmed,I parked in the incorrect parkade. Bear in mind the rush of vehicles going into the parkade,as well as the single board indicating which lane leads to which parkade. I had hoped that with only staying 1.5 hour I would pay like R100. My fee was R540,which I paid as I thought not to make a scene at the machine. Ive reached out to them and the response remains the same,they refuse to make a concession.They refuse to understand that a mistake was made....