Cart gets empty after facebook login

Hi,
I’ve used your plugin and it is working fine,thanks to you.

Goto this page: http://www.smurfers.com/shop/lannister/
I add products to cart, and then proceed to checkout. At checkout,it asks for login.
I select your ‘login with facebook’. Login happens and I’m redirected to same page. BUT CART GETS EMPTY. This should not happen.
Can you help me with it.
Thanks in advance.

https://wordpress.org/plugins/facebookall/