I don't have a non-comcast email account so I cannot use 2 factor identification. Please help!

How to gain access to the new yahoo system replacing comcast email.  I started to follow the instructions but was stopped because I cannot do 2 factor ID with an alternate email.  The one that was used to set up my account was the xfinity salesmans account and I cannot use it.  Please help.

[Edited: "Personal Information"]