Please contact your hosting provider about the ftp login. Usually they send out the ftp login information when you signup for their services. But if they haven’t then you can contact them about it and they will send it to you.
I have restored your site. The code change that you made for the thumbnail-functions.php file had some errors in it.
Meanwhile the login that you sent is for the cPanel where I restored your site. If you need to make any php code changes, then I would recommend you to use cpanel instead of WordPress editor. Use WordPress editor if you need to make any css changes. Also I would recommend you to take a backup of the file before making any changes to it.
Meanwhile the changes you were trying to make is no longer required. There is already an option in theme options to go directly to the post on mouse click. Just navigate to theme options > Portfolio and check “Disable hover and lightbox on hover” which will do the trick.