Have a land line. Not one of the options listed to turn on 2-step verification.
I have to use the 2-step with another e-mail address (which cannot be Yahoo, else a deadlock).
Thus, when I go to Security page to turn OFF 2-step it displays "Turn On".

Plus another issue is
For Privacy controls
California privacy contols is "off".
but
Allow the Sale and Sharing of My Personal Information is "Don't Allow"
and
Limit the Use of My Sensitive Personal Information is "Limit"

In addition, why has Yahoo stopped allowing users to view the entire Feedback page/forum?