Hi Salif,
We got your message regarding the custom value and responded to that here: http://www.nightshiftapps.com/forums/topic/woocommerce-custom-value/
It appears you are currently using multiple Pixel providers could cause problems. Could you please revert to WP Facebook Pixel Pro and let us know when it is activated. We will visit your site to confirm the issues described.
We are working hard on a new update and anticipate releasing it next week. It will include several minor patches as well as set a framework for us to provide some exciting new features!
Regards,
Jacob