Here is some info from IRS.gov (Tax Topic 203) Refund Offsets:

The Department of Treasury's Bureau of the Fiscal Service (BFS) will send you a notice if an offset occurs.  You should contact the agency shown on the notice if you believe you don't owe the debt or if you're disputing the amount taken from your refund.  If you don't receive a notice:

• Contact the BFS's TOP (Treasury Offset Program) call center at 800-304-3107 or TDD 866-297-0517, Monday through Friday 7:30 a.m. to 5 p.m. CST.

Contact BFS to advise them that the loans are closed and to find out your next steps.  TurboTax does not receive any information from BFS regarding offsets.