Pay with a like throwing a fatal error with facebook class

The fatal error I am getting is :
Fatal error: Cannot redeclare class Facebook in pay-with-a-like/lib/facebook-php-sdk/facebook.php on line 160

The plugin worked initially. I installed it yesterday, it worked all day today. Tonight, I think the last thing I did was try and add facebook to the Chat plugin here. I believe that was when I got the error. I deleted the chat plugin, but the error comes back everytime I upload the Pay with a like plugin folder to my server.
What could be causing this? Any help will be appreciated.
Thanks