how do I get back a prior version of Ff and get you to stop installing updates?

I too am losing add-ons even though all of my settings reflect that they should be showing on the site. If I still have the install for Firefox 28 can I uninstall the current version and install version 28? Also do you have a contact email, or is there a way to permanently turn off the updates? Seems that even when I don't have automatic update selected Firefox updates. All of my programs are set to manually update but Ff ignores this setting.