From a press release from Social Security's Office of Inspector General:
Today, I am warning the public about fraudulent letters threatening suspension of Social Security benefits due to COVID-19 or coronavirus-related office closures. Social Security will not suspend or discontinue benefits because their offices are closed.
The Social Security Office of the Inspector General has received reports that Social Security beneficiaries have received letters through the U.S. Mail stating their payments will be suspended or discontinued unless they call a phone number referenced in the letter. Scammers may then mislead beneficiaries into providing personal information or payment via retail gift cards, wire transfers, internet currency, or by mailing cash, to maintain regular benefit payments during this period of COVID-19 office closures. ...