You might try the Office of the Texas Attorney General.
You have to set up a profile on-line.
There is the San Antonio Disbursement Unit that is responsible for all child support payment in the State of Texas.
You can also run your credit report and see if you have been reported for being past due in child support payments.
I agree with Fran's answer. Also, most lawyers in Harris County can look up your name in the records of the Harris County District Clerk. Those records will include any child support cases associated with your name along with a copy of any order that requires you to pay child support.
This communication is not privileged and does not establish an attorney-client relationship.