Legal Question in Criminal Law in Texas

They were assessed against you at the time you were sentenced so there is a judgment for those costs in place. Whether or not you were given credit for time served towards those is a different question. You should go to the district clerk's office in the county in which you were prosecuted and look at (or obtain a copy) of the judgment. If you were given credit, then it will be reflected in the judgment. If you were not, the what is owed will also be on the judgment. If you did not receive credit and you think you were supposed to, talk to the lawyer who represented you about doing a nunc pro tunc (correction to the judgment.) Otherwise, you will have to pay the money or be hounded.