I had the same thing happen last year, after the Microsoft acquisition. I was migrating my repos to a new github account and it was automatically suspended. No email notice or anything. I guess they saw two different accounts logged in at the same IP and that was enough to trigger it.

I contacted them and explained what I was doing and they reinstated it, but I always thought Github allowed and even encouraged "machine users" and thus multiple accounts.

I was definitely annoyed with their heavy-handed approach and lost trust; they could have emailed me first and given me a warning before just automatically shutting my account down and restricting access, assuming I'm a bad actor.