How to lower child support?

I’ve called and called and no one can answer me. Basically my child’s father is paying 900 a month for our 2 kids. According to his check stubs he made 1900 last month. I used to live with him and monthly rent is 890 not including dte, his phone bill and car note.l food ect. It’ll be impossible for him to live comfortably.

I will give him some back if I can’t lower it but they tax is twice so he still loses a lot of his money to the state.

I moved out and me and the kids have Medicaid so I think that’s why it’s so high. But they won’t let me lower it. Anyone else run into this problem?