Millions of Americans received money from the government in the form of rebate checks earlier this year, but there are also those who are still anxiously awaiting their federal refund. According to the Internal Revenue Service more than 6,600 Missourians have had their tax rebate or refund checks returned to the agency. That`s why Senator Jean Carnahan is urging those Missourians who haven`t received their checks to act now. Missouri taxpayers who believe they are missing a check should call the toll-free number 1-888-252-3008 or log on to http://www.carnahan.senate.gov to see if their name is on the list of people whose checks have been returned to the IRS. The deadline to act on the checks is December 5th.