This is one of the toughest problems in the whole divorce scene. Child support enforcement offices tend to be frightfully understaffed and low on motivation. But most states' laws provide huge penalties for employers who lie about whether a person works for them, so it's worth trying to find a staffer who'll listen up. Try showing them some proof of your ex's continued employment -- even a dated snapshot of him driving that company truck could be worth its weight in gold.

If you still don't get any major help from the child support enforcement folks, you could file a contempt of court motion to get your ex back into court. And while you're at it, put a subpoena on the head of the personnel department of both the main company and the division your ex is now working for. The subpoena should order them to bring your ex's employment records to court. Company officials will probably moan and groan about what a terrible imposition this is for them, but you should be able to out-moan anyone who hasn't had to struggle along without the child support they are entitled to.