Expired Parking $85 bill

Hey guys,

I was in Miami Beach last month and paid for 2 hour parking at a building by the marina on Alton Rd. Parking expired as we stayed 1 extra hour. I am getting a bill from Professional Parking Management for $85 threatening to put me on collections, they show a photo of the entry and exit with the license plate on it. How can I fight this, what if I don’t pay?