When this has happened to my sites the script kiddie = hacker has edited the template used to give a single page html output. I see your wp-login.php page still exists so the core wordpress files are still there.
My normal plan of attack to remedy this is outlined below but I think you are lucky in that point 6 has not happened. I can see your site deep pages it by using a site: enquiry in big G and then navigating direct to the page. As such you may just need to log in and change the template to remove the problem. I would try this before doing any restores as you could loose recent data during a restoration.
What to do
1. Log into your hosting platform and restore from a full backup, both site files and the mysql database.
2. If this is not possible see if your hosting provider can quickly restore from a backup they made. If this is fruitless you need to do a repair, check there is no additional code in the .htaccess files, if so edit it out.
3. Use phpmyadmin and restore from a recent database backup you have. If this is not possible check the mysql database for your site - the users table. Often they edit the admin user and substitute their email address. If so insert your correct email.
4. Try to log into your site to repair it. If they have changed your password you can now ask the system to send you a new one ( remember you changed the email address back to yours)
5. When you then get into the site admin change the site template to a different one and check is the site showing your data?
6. If the site looks ok but there are no posts then you really need that backup or you will need to use the Google cache and the Internet Wayback Machine to view your old data and do a manual restore.
When you have access to the site and it looks ok once more be careful. The intruder may have done some other changes which are not obvious and there may be backdoors or trojans hidden somewhere. A full restore can eliminate this possibility.
Good Luck!
