[TX] NCP avoiding being served.

I am currently working on a custody change order pro se. I have already submitted the petition and initiated the NCP to get served as he will not sign a waiver. Even before this custody change request, he has never updated me on where he lives or where he works and I am unable to find either addresses. All I could get was his apartment complex address, but even then I am not 100% sure. The last server called him and went to a previous address and NCP said he works out of town and doesn’t know when he will be back. This is not true, he does not work out of town. I also reached out to him requesting an address and he refuses to provide one which is actually against our current custody agreement. What can I do to get him served or is there any other way to move this case along?