I tried getting an updated EIN letter for months (updated business addresses among other htings). For the first 2 months of 2023, they were "too busy" and the phone just cut out. I just called now and they picked right up.

If anyone needs an updated EIN letter, call the IRS. 800-829-4933 ext 3.
I used https://www.faxburner.com to get the faxes.