Missouri allows you to see how long you'll have to wait for your state tax refund with a call to the state's Department of Revenue at (573) 526-8299. If the phone isn't an option, you can also check online through the Department's website.
You must have your Social Security number, your filing status and the refund amount on hand before you check. The state requires all of that information whether you're checking online or over the phone.
If you moved between the time the return was filed and the refund check was mailed, update your address at the State of Missouri's address change request page. If your check was returned to the state, you will need to provide your name, last four digits of your Social Security number and your new address to the state. Send it by email to email@example.com, or mail it to the Missouri Department of Revenue, P.O. Box 2200, Jefferson City, Missouri 65105-2200.