Hi there,

It would be possible to add this PHP code snippet to your site:

global $marketkingpro_public;
add_action( 'your_hook_here', array($marketkingpro_public, 'marketking_refund_button'));

(and replace your_hook_here with a hook)

This requires that the hook passes $order as the first parameter. 

If it helps, this is the function our plugin uses for that refund button: https://pastecode.io/s/68pigw44 

I can also try to make modifications to that if needed, and/or create a custom shortcode

Kind regards,

Stefan