My question involves civil rights in the State of: Texas

Not sure if this is the right forum but here it goes... Recently recieved a letter from the City of Houston over a red light camera violation that was commited by a vehicle I used to own prior to the violation.
The letter states if I do not send them their violation money they intend to disclose to one or more credit bureaus that I am delinquent in payments, The Texas Transportation Code states very clearly in Chapter 707 that this cannot be done "(h) A local authority or the person with which the local authority contracts for the administration and enforcement of a photographic traffic signal enforcement system may not provide information about a civil penalty imposed under this chapter to a credit bureau, as defined by Section 392.001, Finance Code. Now in the same letter from Houston it States that pursuant to Texas Transportation Code Chapter 707 that since I did not respond in the correct amount of time from the first letter that I admit liability and waived my right to an appeal. Seems to me they should not be able to pick and choose regulations.
Can they do this and is there an intity in Texas that enforces these rules, I also have proof that I did not even own the vehicle at the time, with proof of insurance Cancellation of 2 months prior to the violation plus a bill of sale from the individual that purchased the vehicle also 2 months prior, They also threaten me with a lawsuit and they will seek court cost when they win.... All they have is a photo of a car with my old license plate number on it.