What if it was my year to claim my child and his father claimed part of him anyway? How?

First, there is no provision in the tax law to claim part of a child. Either you get the whole deduction or you get no deduction. If the court order specifies that you get the deduction this year, take the deduction on your return and see what happens. There is a chance that the child's father is lying about taking the deduction (surprising how often this happens), if you both claim then you have the court order giving you the deduction; when IRS asks for supporting documents?

He is in violation of the order, see an attorney and seek to collect your damages.