@avincent61
As a custodial parent, I do not "get $2000 more" on my tax refund. I claim the child tax "credit", which lowers my AGI. This statement is incorrect .... the CTC does NOT reduce your AGI it reduces your tax liability $ for $ until your tax liability is reduced to zero ... then any unused portion can be come refundable up to $1400 per child.
IRS only awards a percentage of his tax return to me for that backed support. The IRS just does what it is told to do ... he probably makes sure he has no or little refund to attach or the refund must be divided among several claims against it.
Everything else you mention is a personal matter to take up with the courts ... the IRS has no skin in that game and cannot will not get involved.
