I may have told this before, but I was the domicile parent, so my ex paid me monthly, not much, under $500 for three kids, I banked it all for their college. Anyway, one month it didn't come, the next month it didn't come, so I mentioned it to her and she flew off the handle at me (as usual), it was somehow my fault.
So, I do nothing about it until I get a call from Children's Service harassing me for not paying child support. I kindly inform the lady that I'm on the other end of this equation, she checks her papers, and says she'll call me back. Whatever.
A week later my ex calls me all mad because a county sheriff showed up at her door saying he would arrest her if she didn't pay up, again, my fault.
The deal was she had changed checking accounts and not bothered to change the monthly payments. Anyway, it got sorted out, I didn't go to jail. I think I got the back pay, which I had asked to be reduced in the divorce because I thought it was way too much. I think it was supposed to be $1500 or so a month, for three kids, while I was making a pretty nice salary. Crazy I know.