In Ex parte Dustman, 538 S.W.2d 409 (Tex. 1976), after the trial court issued a contempt order confining the relator for failing to pay child support, we ordered the relator discharged when his uncontroverted testimony demonstrated that he was unable to pay the amount in arrears. Id. at 410. Because the relator's testimony was "'clear and positive, and there are no circumstances in evidence tending to discredit or impeach it,'" we found that the relator had established his inability to pay as a matter of law. Id. Accordingly, the Court held that the trial court exceeded its authority by ordering him confined. Id.