How to make Comment Review option work in any theme
If you're using WP Product Review and the user comment review option is still not appearing after activating it, then it's probably an issue with your theme's comments.php file. It usually happens when theme developers use custom comment form templates.
It could be solved by first creating a child theme for your theme (contact your theme developer about this).
Copy the comments.php file from your parent theme to your child theme, then add the following snippet to just above the textbox code in your comments.php file:
<?php do_action('comment_form_after_fields'); ?>
If you're not comfortable fulfilling these steps then please contact your theme developer and they should be able to assist.