In response to the economic impacts of COVID-19, the U.S. Government issued checks to U.S. citizens and permanent residents. International students are not eligible for these payments. Nonetheless, some international students have reported receiving a payment.
Any international students, staff or faculty who received stimulus payments should document the return of the funds to the IRS. More information from the IRS here: https://www.irs.gov/coronavirus/economic-impact-payment-information-center
OISS is not able to advise you regarding these payments or other tax-related questions.