I ran into the same scenario as you, hopefully yours resolves quicker. I filed in April and in November contacted IRS for escalation and Senators office (they referred me to Tax Payer advocate). Multiple correspondents and "escalations" with all 3 since then and still no resolution. Newest update from Tax Payer advocate (I've been told different things by different people) is that the errors and resolutions department was closed since Covid started and only recently opened up and has a huge backlog. The Taxpayer Advocate put in an Operations assistance request with a request for resolution by February.
