I'm trying really hard to have patience, but a lot of people here need to have a good heart-to-heart with customer support somewhere else.

Go to your email provider. That's all there is. If you have Gmail, go to www.gmail.com and log in. I'm sorry, but there's nothing to help you with.

Firefox is a web browser and not a email client.

Most Internet Providers you use to connect online with have a form of webmail so you can do email in web browser. Ot you can one of the many email services out there like gmail, hotmail, yahoo to name a few.