My ex own 2 years of Child Support and he own money to the IRS too. I am getting something for backup child support or the IRS take everything?
The IRS will take what is owed to them out of the refund first. Any refund left after the IRS debt is paid should go towards the back Child Support.
You can check out IRS Topic No. 203 for more information on Refund Offsets: https://www.irs.gov/taxtopics/tc203.