Skype accounts are Microsoft accounts. That's why the sign in page says "email, phone, or skype." But Microsoft did a spam purge as well, that's why Skype is us

Skype accounts are Microsoft accounts. That's why the sign in page says "email, phone, or skype." But Microsoft did a spam purge as well, that's why Skype is usable again. If your Skype account was compromised and being used to send spam, it's probably gone for good.