We had the same problem. I had to go in via FTP and remove the plugin folder, That brought the site back online. Then when I tried to log into the admin account I was prompted to remove three other files from wp-content in order to log into the site. You can do all of this via FTP. That will at least get you back into the site and get your site online. I am still troubleshooting how to reinstall or completely remove the plugin. Hope this helps.