To get the like count of any page on facebook, you can use this method below.
Create a new Call with this in the Get url:
https://graph.facebook.com/v2.2/[fan_page]?fields=fan_count&access_token=123456yourtokenforyourapp
Note: you need an access token for your app.
This url will create a key with fan_page. Uncheck private.
The object you want to get the likes count is called ‘fan_count’.
Here is a picture of my setup.
Cheers
Jason Smith