I cannot login to Firefox.

I have been working with Sofia at Mozilla. She told me I needed to contact Firefox for help regarding inability to login. However, this is as far as I got, Mozilla Support. When Mozilla first made their entry into the world, I remember an email stating that we didn't need to create a new login or password. Up until 2-3 weeks ago, I have been using the same login name (email address) and password. For the past week or so, I haven't been able to login into Firefox.com or accounts.firefox.com or anything with the word Firefox in the URL. Each time I attempt to login to Firefox Browser a page appears telling me to download Firefox, which I have done. I now have at least 20 profiles. Why can't I login to the Firefox Browser? PLEASE HELP ME with understandable languague. I'm able to get to this page, and I know you are going to tell me I need to go to Firefox Help. Okay, how do I do that? AND remember, I am unable to open Firefox Browser.