Unfortunately this IS MI you are dealing with...they probably won't do anything.
I'd try to get more $$ out of him on your own by telling him you'll take the evidence to court.
Sorry that I'm a little jaded when it comes to MI courts doing anything to help or caring that he's lying. My ex lied to the courts stating that he was under the age of 18 and still in high school so he didn't have to pay child support. He was a high school drop out but the issue really was that his age was stated as 17. I asked them "don't you even check drivers licenses or birth certificates cause he's not a minor?" They didn't care and told me I had to wait 2 years to review it. 2 years that I didn't get ANY support at all.