When I was a sysadmin at the Naval Research Laboratory in the 80s, I was asked to install Icon, Ralph Griswold’s follow-on language to SNOBOL. I had a little trouble installing it on our Gould minicomputer and mailed in a support request. It was answered by Griswold himself! I felt special! (It was just a Makefile issue, as I recall. This was the era of tar source file distribution. No rpms, no snaps, no debs.)
Not sure if this means snail mail, but I don't know why I never considered that before email, people used physical mail for things like tech support, heck, maybe submitting patches