function save_online_shop($post_id) {

    if(get_post_meta($post_id, '', true)) {
        if(get_post_meta($post_id, 'wpcf-proprty_online', false)) {
            if(get_post_meta($post_id, 'wpcf-proprty_online', true) == 'y')
            {
                    wp_set_post_terms( $post_id, 75, 'region' );
            }
        }
    }
}

add_action('save_post_listing', 'save_online_shop', 999999);