The I-R-S is holding checks for nearly a thousand Iowans — checks that were returned to the agency by the post office as undeliverable. I-R-S spokeswoman Donna Migazzi says there are many more checks being returned this year than usual.This year the returned checks include ordinary income-tax refund checks and advance child tax credit checks. The agency’s list of undelivered checks for Iowa taxpayers this year totals more than 490-thousand dollars. Migazzi says they range from as low as one-dollar to as high as nine-thousand-400 dollars. About 972 checks have been returned from Iowans’ mailboxes as undeliverable. Migazzi says Iowans who think they may be missing a check or two from the I-R-S can check quickly on-line. The I-R-S website at “” enables taxpayers to track the status of refunds. If a problem is found, call the agency at 800-TAX-1040. Migazzi says taxpayers who want the advance child tax credit payment must update their addresses by December 5 so the checks can be reissued before December 31. Taxpayers who miss the cutoff won’t miss their child tax credit, however, because they can claim the credit on their 2003 return next year.