Key file lost, during content update, following latest upgrade

Martin and colleagues, I've used the site for years; and, contributed, in the past. Tonight, immediately following installation of the latest update, the site crashed and locked, while I was transmitting changes to the index page. That apparently wiped out the entire index page file; and, has generated an error code and access warning, on the Internet. The site is ConnVerge.com. I'm a permanently disabled Naval Officer veteran with wartime service; and, would welcome all support in reinstalling a saved copy of that file. Many, many thanks. Steve

Do you mean you have lost even your local copy of the file? Or were editing the file of the server? (so you have no local copy of the file). In that case, please try to contact your hosting provider, in case they do have a backup of your site.