When I had a job at HUD answering phones I made up a cheat sheet with all the information people were likely, or even unlikely, to ask for (oddly,legal aid and even sexual violence help) complete with phone numbers and names, if I could get them. That helped a lot with anxiety working the phones.

For making calls in regular life a beta blocker might help. It won't mess you up like a benzo might but it could at least take care of the physical symptoms like shakes and heart-pounding etc.