We understand your frustration. As we have said, this issue has something to do with your server’s file permission by which only your hosting provider can resolved. Please understand that after the update as you have said, the Dashboard, Home and Updates were missing. You cannot upload a theme or add a new plugin either.
So I went ahead and logged to our ftp again and investigated most of your WP files. I found out that there is a restriction added in your wp-config.php file.
I have removed the lines and here it is. The Dashboard, Home, Updates, Add A New Theme, Theme Editor, Add new plugin and the Plugin Editor is back right in your dashboard.
Please check your site now.