My personal residence is in Portland, Oregon / Multnomah County; my business residence is in Beaverton, Oregon / Washington County.
I did reach out to the City of Portland after receiving the notice and they told me that they only accept and look at Federal Tax Returns (I have offered proof of residency for both personal and business, told them that they can send me mail to my business address, and/or they can talk with the owner of the office building who is a client of mine, but they refuse to consider any of those).
I did reach out to a couple of CPAs (I haven't heard back from them given the upcoming October deadline) and a Tax Attorney, who recommended amending the returns and submitted the new ones to Portland once they are approved by the IRS.
Overall, I'm at a loss, other than submitting amended returns, though they may take awhile as you mentioned.
Thank you again for your advice; I really appreciate it!
