I realize that this is something you are passionate about (Dad paying what he is supposed to). I have been there, and went down much the same path as you.
Got my contempt motion heard, and I won. Dad didn't pay off the judge's orders (on the contempt issue). Judge turned it into a judgment against the X. I turned the X over to collections.
Then I was thinking "well, if he can't be an involved parent, he can at least financially responsible and help take care of his children that way!"
NOW? I have come to the realization and understanding that some parents just won't/can't/don't be a parent--emotionally, physically or financially. And once I wrapped my brain around that bit of truth; I realized that me forcing the matter and going to great lengths to "make him pay" was only allowing the X to still be in control of my life (to some degree) and there was NOTHING that I could do to "make" the X step up and do anything he didn't want to do.
After I quit stressing the idea that X was a "deadbeat dad", my mental and emotional states were so much better.
And when my current husband chose to adopt the children (after their birth father asked my husband if he wanted to adopt the kids), I was even able to forgive $1600 in child support arrears!
I said all of that to say this: You are NEVER, EVER going to force your Ex to do the right thing. If he doesn't think he should have to pay, he just won't! And if you continue down this vindictive road, you will end up one sad, beaten and angry woman!