What are the name and phone of the customer with the most ordered product quantity?
select t1.customer_name, t1.customer_phone from customers as t1 join customer_orders as t2 on t1.customer_id = t2.customer_id join order_items as t3 on t3.order_id = t2.order_id group by t1.customer_id order by sum(t3.order_quantity) desc limit 1