You should request a copy of the front and back of the refund check by calling the Comptroller's Office at 1-800-877-8078. Once you receive the copy of the check, use the signature on the back of the check to verify it was cashed by someone else. If it was cashed by someone else, send a copy of the cashed check along with a request for a forgery packet to:
ILLINOIS DEPARTMENT OF REVENUE
PO BOX 19001
SPRINGFIELD IL 62794-9001
You will receive a letter with forged warrant affidavits that need to be signed and notarized, along with a claim form and a direct deposit form. Complete and return this information to us for review. You will be issued a replacement check if it is determined that the original refund check was cashed by someone else.