I relocated from FL to MO on April 14, 2021 and I had requested extension to file 2020. I mistakenly entered MO in my address. How do I stop MO from billing me for 2020?

[FOTBOB]

I relocated from Florida to Missouri on April 14, 2021, and I had requested an extension to file my 2020 tax return.  Unfortunately, there was an error in the address and the state information on my return that has led to billing discrepancies.  Initially, when I completed my 2020 tax return, I mistakenly entered my St. Louis, Missouri address instead of my Ocala, Florida address, where I had lived and worked in 2020.  Realizing the error, I updated my address; however, I inadvertently failed to correct the state from Missouri to Florida.  This mistake appears to have triggered the Missouri Department of Revenue to bill me for the year 2020.  Despite my best efforts, I have been unsuccessful in resolving this matter, and I recently received a certified notice of intent to offset individual income tax from the Missouri Department of Revenue for the amount of $1,445.  If anyone has any specific instructions or recommendations on how to handle this situation, please do share them.  Thank you so much for your guidance, and I look forward to your response.

[tagteam]

Have you tried contacting them?

https://dor.mo.gov/contact