I got an email at my old email address saying I didn't sign in for 2 years.

Almost 3 years ago I got married and changed my last name. My Hotmail address has my old last name, so I started a new Outlook address & tried to get started here using that. I was hoping that any email from Mozilla would go to the Outlook address, but I just got an email at the Hotmail address saying that I hadn't signed in for 2 years. I do remember a few times I had trouble signing in. The "owner" of this computer is still me - using my maiden name - if that matters. Now I don't know if I have more than one Mozilla account or what. Is there some way I can get things sorted out?