You will absolutely have to repay the funds to the US Department of Education or to the federal student loan holder or servicer.
How does one think they got a high school diploma but they actually don't have one?
This may occur because your high school is a diploma mill that charges a student a fee and requires him or her to complete little or no course work to get the diploma.
What happens if I accidentally received more federal student loan or grant money than I was supposed to receive?