taxes were offset

My sons taxes are being offset due to money owed from previous years. I have seen at least 10 news articles as well as even on a Congressmans Official website that only those owing child support would have their 2019 RETURN offset or garnished, including taxes owed from previous years. Each thing I have read clearly says RETURN not Stimulus payment. How do you go about getting your offset returned to you when a mistake has been made? It has so far been impossible to talk to anyone on the phone when calling the 1040 IRS number or the number given to call about the offset on the Wheres My Refund offset notice .