If the parent is not allowing access and there is no support order, you may file a child support case with the OAG to establish a child support order that addresses parenting time/visitation or file a case with a district court. Either parent, custodial or noncustodial, can apply for child support services through the OAG to establish an order. Unlike when you hire a private attorney to pursue a legal matter on your behalf, the assistant attorneys general represent the State of Texas, not the parents. The applicant cannot specify which legal actions are pursued by the OAG.
Without a court order in place, there is nothing that the state can do to get the other parent to let you see your child. A court order signed by a judge protects your parental rights by allowing you to use the legal system to enforce the order if you need to.