If your wordpress site is suddenly displaying garbage (a.k.a. someone elses pages) then you’ve been hacked. If you log in as administrator you’ll notice that your content should all be there and intact.
What they have done is modified your htaccess file.
To quickly restore your site to its’ former glory, I recommend simply:
- add the Bulletproof plugin in WordPress.
- Generate a sucure htaccess file (using the plugin)
- Select each option one by one and activate (enable) them all.
Your site should be back up and running normally.