Just wondering

Ok so I got divorced in 2015 and in my divorce child support was put into play! 4 years ago my x moved with my 2 boys away from az to Tennessee without me knowing! I've never received anything saying they were trying to collect child support but now my mother in law revived something from Tennessee child support at her home in CA which i am not at!! Is the same order in place as when we got divorced? One if my boys is 19 now the other is 17 idk why they just started coming after me? Is that normal? Thank you for any info you can give me!