If this happened within the last thirty days, you can file a motion for new trial explaining that through bo fault of your own you were not given notice of the hearing, did not have a chance to participate in the proceedings, did not ever agree to all this (hopefully you didn't sign a waiver of service saying you didn't request notice of hearing and were fine with whatever happened?), and that you have important rvidence for the court that you feel would make a difference in deciding custody, and was not available to the court due to your not knowing about the hearing. Motions for new trial are not the easiest thing to deal with procedurally (there are a lot of steps and procedural requirements involved), and honestly I don't really know what your chances would be of getting it all done right by yourself, but the rules do explain all that and forms for the documents you'll need should be available at gour county law library or maybe even online. You may even be able to do something here if it's past the thirty days, but that gets even more complicated, so if there's any way you can just get a motion for new trial filed within thirty days, your chances are a lot better. I don't know if they have anything specific to MNTs, but there's a website that I think is kind of supported by the State Bar, texaslawhelp.com, that might have something useful information for you. Otherwise, you might try your county law library, because I really don't know how accurate any of the online materials intended for pro se use are--I imagine they vary quite a bit. Good luck.
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