@lancerb1 said: "When I hired on during Covid in January 2021, my residence wasn't settled (I ended up buying a house, where I work 100% remotely, on the Illinois side of the Mississippi river). My Missouri employer began Missouri witholding by default"
Where were you living prior to establishing IL residency? If MO, you probably shoulda filed a partial year resident return, rather than non resident.
I suggest you call MO DOR, explain your situation and get specific instruction for the appeal. It sounds like you just need to write a letter explaining the details of the situation (something that couldn't be done just by filing standard forms).
