Got a parking citation but I wasn’t even in Houston

I got a ticket for Parking violation at the airport, only problem is both me and my car were in Dallas and haven’t been to Houston in years. I tried to challenge the citation, sharing toll details of my commute in Dallas but they rejected my claims. Luckily I had additional proof I was in Dallas because I was charging my car at home in the garage. I shared all that information with them and got no response. Today, I got a letter in the mail with the fine standing plus a late fee. I’m at a loss on what to do. There is no phone number for park Houston and they seemingly just ignored my email. I’m glad to pay when I’ve made a mistake but this seems like they’re sticking me up! Any suggestions would be appreciated.