Block hotlinking not working

Hi, I’m trying to block a website that is linking our content without permission. I’m using an htaccess file, but does not work. I followed the wiki instructions and several web pages in Google to do this but still not working.
This is the content of my htaccess file (located at the root of the domain):

RewriteEngine On
RewriteCond %{HTTP_REFERER} ^http://(www.)?$ [NC,OR]
RewriteCond %{HTTP_REFERER} ^http://(www.)?$ [NC] RewriteCond %{HTTP_REFERER} !^$
RewriteRule .(jpeg|JPEG|MP4|mp4|m4v)$ - [F]

BEGIN WordPress

RewriteEngine On RewriteBase / RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /index.php [L]

END WordPress

Please, can anyone help me? thanks!