Thanks to Michelle Singletary, financial writer for the Washington Post, for this helpful info. Lots of Americans may have thrown out what looked like junk mail but really contained not a stimulus check but a stimulus debit card. The cards were sent in May and June from MetaBank and came in a plain envelope with no governmental IRS or Treasury markings. Just another glitch in these trying times.
So the Treasury is sending out reminder letters with a return address: Economic Impact payment Card, PO Box 247022, Omaha, NE 68124-7022. The letter provides instructions to call customer service: 800-240-8100 to report the card lost or stolen or to get a free replacement card.
Source: Financial Planning for Women