Facebook now requires its users to verify ownership of Facebook Pages that have a ‘large number’ of fans.
If that’s not an option since you don’t control the website, there’s another way for you to authenticate a page. You can add a second email address to your Facebook account that is officially affiliated with the brand that your Facebook Page represents.
Once you have done that, just submit your authentication request to facebook.com.
source : http://www.labnol.org/internet/verify-facebook-pages/14074/
To authenticate your Facebook page, you need to add a Facebook Fan widget or a Facebook Badge to your website home page and link it to your main Facebook page.Our records indicate that you are currently the admin of a Facebook Page with a large number of fans, Digital Inspiration. To ensure a positive user experience, we require admins of large Pages to confirm their affiliation with the brand, business, person, or entity that their Page represents.
If that’s not an option since you don’t control the website, there’s another way for you to authenticate a page. You can add a second email address to your Facebook account that is officially affiliated with the brand that your Facebook Page represents.
Once you have done that, just submit your authentication request to facebook.com.
source : http://www.labnol.org/internet/verify-facebook-pages/14074/