Ok ... first the IRS can delay the payout for up to 6 months to allow for an injured spouse form to be filed if the delinquent party is married ... nothing you can do to speed up that process.
AND ... if the delinquent party owes back child support then why do you think they even have a refund on their return ? A wise person would under withhold on purpose so they owe on the return thus there is nothing to grab for child support ... this is a common situation which again you can do nothing about.
Finally ... all situations that required human interaction on both the IRS and child support agency sides will take much longer this year due to the 3 month shut down in those agencies ... sadly nothing you can do to speed up the process here either.
