I never received my third stimulus check so I called them. It was the number listed at the bottom of the letter. Also, this was just a month ago so probably way past the time most people tried to resolve issues. I also called them right when they opened.
I got through and the lady was very nice. There was a 0 added to my address just right in the middle of nowhere. Probably a sloppy typist. I was put on hold for about 20 minutes but everything was resolved and I received my check a few days ago.
I don’t know if any of what I stated above will help.
I deal with another US government agency often because of my job. So I understand the frustration all too well.
The special numbers as mentioned above are a huge help. Also, if you can get personal telephone numbers or maybe personal email addresses, this is also very helpful.
Don’t know if how this is done at the IRS. Maybe.