Firefox is a Web Browser, it doesn't have anything to do with your emails. You can go to a website that shows your emails (uch as Gmail, Yahoo, AOL, etc.) and view your emails using firefox, but Firefox doesn't have anything to do with them. so no, to get back lost emails mozilla can't help.

Thank you for your reply. I realized that if I went to Internet Explorer, I could get my emails back. You go to delete and there is a choice to recover deleted emails. When I did thatl 33 emails went into deleted. Then I just picked the ones that go into my inbox and delete the rest.