Outlook/Hotmail needs security info and directs me to an email address I had 15 years ago that I can’t access now.

When I try to sign into Hotmail I am being told I need to answer questions within 5 days to "increase security".  When I answer the question, it says a "code" is being sent, but it is being sent to an email address that I had over 15 years ago with Comcast.  I can't even access that email.  So, willl my Hotmail account that I have been using for 15 years get shut down?  How to avoid this?  I don't even know if I will be able to see any responses to my query on this forum as my "handle" here does not match my Hotmail handle.  I am so frustrated that I can't even formulate proper questions.  Any wisdom?