They kept putting me off, saying we need more time ... for 9 months ... until they finally looked at what I sent them and essentially said "never mind" and closed the case. In all this time (until they folded) they were saying I owed $2,900 plus interest and penalties, and of course the interest and penalties were continuing to accumulate. 9 months is a long time to have that hanging over me.
This is the summary of the timeline.
https://www.democraticunderground.com/11212509#post18
# 11/12/20 - I got the CP2000 claiming that I didn't report $10,000 in Beneficiary IRA RMD distributions for 2018 taxes, thus under-reporting my taxable income by $10,000. So I owe $2,900 in taxes due to that and some secondary effects that I won't bother to go into and including $190 in penalty interest. (see OP for details)
# 11/16/20 - I mailed my response to the IRS CP2000
# 2/5/21 - Got a response -- the first time I heard from them -- "We received your reply on Nov. 20, 2020 to our notice about proposed changes to some of the items on your tax return. Before we resolve this matter, we need to process all of your information. We'll send you our complete response within 90 days."
# 5/8/21 - Got another response - IRS 5/3/21 letter received 5/8/21 - "Before we can resolve this matter, we need to process all of your information. We'll send you our complete response within 90 days.
# 8/3/21 - Got another response - IRS 8/2/21 letter received 8/3/21 - same as above
# 8/26/21 - Got a letter, "we're pleased to tell you that the information you provided resolved the tax issue in question and that our inquiry is now closed".