I got invoiced unfairly by Hertz for an unpaid parking fee, what are my options?

So just came back from Norway- we rented a car from Hertz and had amazing road trips. We are back in the US, having successfully returned the car and everything seems to be in order. 3 weeks later, we get a charge from Hertz for around 530NOK ($53)- according to an invoice- it was for an unpaid parking at one of the glacier park. The problem is, we have the receipt that shows we paid for the parking. The receipt clearly shows the place, date and time of the payment. I know Hertz is just a messenger and is passing along the ticket, but Hertz is charging us 300NOK ($30USD) administrative fee, and they are tacking on all these fees and VAT to charge our CC $53 for a $13 ticket… I don’t mind paying if I was at fault, but we were very conscientious and proactive in paying all the parking wherever we went. We sent the receipt to Hertz, and asked them to reverse the charge- it’s been 5 days, and still no response.. So what are my options?? Can I go through my credit card to reverse charges?? What is the repercussion of that?? Or, should I just take the hit, and consider this as a “cost of doing business “