Non-Texan here. Why do I keep receiving bills from the "Harris County Toll Authority" for unpaid toll violations?

Does this agency commonly send bogus toll notices to unsuspecting people? I first received one of these in February. Figured it was a scam so I threw it in the garbage. Then another one came a month later. It's addressed to my name and home address, but the car in the photo isn't mine. I called the toll agency and explained this to them. They said it was probably a clerical error and to ignore it. A month later, another bill comes, this time threatening to send me to collections. I call them again. They say my name must have got mixed up with the actual owner and they would note in the system to stop sending me these notices. Today, I get another letter with more fines and collection threats.

I am completely mystified as to why I am getting these letters. I do not live in Texas. I have never lived in Texas. I have never worked in Texas. I have never owned property in Texas. I have never purchased a car from someone in Texas. I have never sold a car to someone from Texas. I have never owned a car of the same make/model pictured in the letter I received. I have never even been to Houston, unless you count brief airport layovers. The only time I've ever rented a car in Texas was like 10 years ago for a wedding in Austin.

I live in California. I have always lived in California. Why am I getting bills from a toll authority in Houston? How did they even get my home address? I'm honestly pretty fucking annoyed that some local transit agency 2,000 miles away in another state I have no association with (and which has no jurisdiction over me) is insisting I somehow owe them money and threatening to send me to collections and damage my credit rating. Is this like thing this agency commonly does or something? I've already called them twice and explained the situation, yet the letters keep coming. Not really sure what to do.