I would guess that at least 2 of the 3 lettered government agencies would love to have an interview with you. This might be extremely helpful to nail him and place him behind bars. That however, unfortunately, won’t get you child support. The head of GRNF is a serial scammer and con artist, in my opinion, I am sure your thoughts are at least that and possibly much worse.
Please feel free to vent on this board anytime you desire for support. You are not alone. Friends can help.