Pay with a like not working at all

I have managed to get "Pay with a like" to display properly using the temp fix recommended here https://premium.wpmudev.org/forums/topic/pay-with-a-like-display-is-too-narrow#post-824868 but now it simply doesn't work at all.

On clicking the "recommend" button the dialog box appears to open properly and the "add comment" button is inactive until a comment is typed (see screen cap 1 and 2) .

On clicking the add comment button, nothing happens. It neither shares to Facebook nor reveals the hidden content.

Please treat this as urgent, this project is now a month over deadline.