Need help updating my product inventory on the WooCommerce manage orders page. I currently have some code that works, but it removes inventory from the wrong product. Does anyone know why?

add_action( 'woocommerce_after_order_itemmeta', 'action_woocommerce_order_item_add_button', 10, 2);

function action_woocommerce_order_item_add_button($item_id, $item)
{
  $product = $item->get_product();
    $id = $item->get_product_id();

        echo '' . __( 'Töm lagersaldo', 'hungred' ) . 
            '';
    
}

add_action('save_post', 'renew_save_again', 10, 3);
function renew_save_again($post_id, $post, $update){
    $slug = 'shop_order';
    if(is_admin()){
            // If this isn't a 'woocommercer order' post, don't update it.
            if ( $slug != $post->post_type ) {
                    return;
            }

            if(isset($_POST['renew_order_single_product']) && $_POST['renew_order_single_product']){
    
                //removes stock for specified product
                global $woocommerce;
                $quantity = 0;
                $product_id = $_POST['renew_order_single_product'];
                $woocmmerce_instance = new WC_Product($product_id);
                $new_quantity=wc_update_product_stock( $woocmmerce_instance, $quantity);
        
         }
    }
}