You can clear your cache and cookies for the site as well remove it from History :

• https://support.mozilla.org/en-US/kb/how-clear-firefox-cache
• https://support.mozilla.org/en-US/kb/delete-cookies-remove-info-websites-stored
• https://blog.mozilla.org/theden/2012/06/28/remove-a-single-website-from-your-firefox-history/

Please let us know if this solved your issue or if need further assistance.

Clearing the cache works for a little while, but in a couple of days problem returns. And clearing cache doesn't make sense, when I click to go to site shouldn't the cache be reset? Why would back page take me anywhere but where I came from?

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)