Whats worse, is something like this happened to me on Yahoo, except instead of not being able to login, they simply deleted my account. they said my account no longer existed. I never used any yahoo product for anything serious, after that.
-Use another phone or computer to finish signing in
I always use the browser in incognito mode. This option does not apply to me (it will not work).
-Answer your security question I don't remember (I think I put something random) to make the account more secure.
-Get help It asks for the last password, but it doesn't work. Broken?