I had the opposite experience. Github only recognised my institutions student e-mail domain, not our institutional one that instructors and staff use. So I couldn't sign up as an instructor for the educational stuff.

I sent in a tech support request, and it was solved in less than 2 hours. They even replied, telling me they added my institutional e-mail domain.

So not only did a human reply and fix my problem, I'm not even a paying customer. I get the free education account.