Prevent users from posting multiple review on a single post in WP Product Review

WP Product Review allows users to post as many reviews as they want to a post. It's the default behavior but it can be changed by adding the following snippet to your functions.php file:

function remove_review_comments() {
	global $post;
	global $current_user;
	if ( is_singular( $post->ID ) && is_user_logged_in() ) {
		$current_user = wp_get_current_user();
		$usercomment = get_comments( array( 'user_id' => $current_user->ID, 'post_id'=>$post->ID ) );
		if( $usercomment ) {
			remove_action( 'comment_form_logged_in_after', 'cwp_additional_fields' );
			remove_action( 'comment_form_after_fields', 'cwp_additional_fields' );
add_action( 'pre_get_posts', 'remove_review_comments', 99 );

Adding this should prevent users from posting another review on the post, without preventing them from making new comments. It only works for logged in users.