How a father is to contact sons from a mother who purposefully avoids him.

How does a father find his children when the mother is purposefully avoiding ALL contact?? Why is it he cannot report his children missing. Wondering if that is the law there in Bloomfield. Police seem to like harboring this woman too, because they're friends with her.

I would also like to add. That the father is a "GOOD" father. Pays his child support every single month, ON TIME, sends them whatever they need, AND tries almost every single day to call them, several times a day at that.
It doesn't matter when he calls no one will answer. He does NOT live in state anymore. However, in a year and half she has only allowed one of their sons 4 phone calls. He hasn't heard from ANY of his sons since Feb. of this year. Doesn't that constitute them as missing, if he cannot reach them and does NOT know exactly where they are? I'm not getting how this can NOT constitute either a missing persons report or even parental kidnapping.