If my kid's dad filed taxes and owes me child support, do I get any of his tax money?

My kids are 15 & 17yrs old. I 1st filed for child support in 2002. Last I knew, their dad was over 30,000 behind. I received government assistance from 2002-2006 (I mention it, because I do believe it matters). My kid's dad claims he filed taxes last year, that's the first time I know of (he never kept a job long enough). He says he also filed again this year. With him being behind on child support, shouldn't I had received at least some of his tax money? Because I received none!! & am wondering if I will this year?? He told me that child support took his tax money, so I'm just curious as to why I received absolutely none!?