Harris county toll road authority linbarger goggan blair& sampson, llp trying to charge me for tolls that have already been payed. Texas

 after paying tolls that were said to be owed. They still sent my info to the collection agency as if I hadn't payed , and now I have a document saying the tolls were not payed and I not only owe the tolls , but also huge fees , and if i don't pay they can put a device on my car to keep me from driving. the funny thing is I have an easy tag and I had to pay those tolls in order in order to get it...the vehicle with reported violations is no longer registered to me hasn't been for over a year. So how is this legal?