Go ahead with the garnishment. I was afraid to do this, too and my X cried bloody hell when he was notified. But, the thing is he agreed to pay so much over a year ago and the court signed off on it. It was less than the guideline amount for my state by several hundred dollars--because I didn't want to send him to the poorhouse. He paid me directly for several months but then he started getting later and later and quit paying altogether. He was still golfing every week and then got himself a new car but I'm not supposed to care about that, right?
In my state we have an income shares model so I make more money and pay more of what the kids need. The small amount that he is supposed to pay, though really does make a difference and I was determined to hold him to the agreement. I let him know ahead of time what I intended to do and when that didn't work I let the child support enforcement agency in my area take over. Payments have been regular ever since. It's worth it. Now, if I could just get him to help me out with medical. I carry insurance on our 3 children, he is to pay 1/2 out of pocket expenses (I am to pay the other 1/2). I have been paying 100% for the last 6 months. You know, I gotta think he doesn't have a clue what the costs are for raising these kids. Either that are he doesn't care. I seriously hope it cluelessness and not carelessness.