What is the contact name and phone number of the customer who has made the most total payment on the order to date?
most total payment = Max(Multiply(Quantity, UnitPrice, Subtract(1, Discount)))
SELECT T1.ContactName, T1.Phone FROM Customers AS T1 INNER JOIN Orders AS T2 ON T1.CustomerID = T2.CustomerID INNER JOIN `Order Details` AS T3 ON T2.OrderID = T3.OrderID GROUP BY T2.OrderID, T1.ContactName, T1.Phone ORDER BY SUM(T3.UnitPrice * T3.Quantity * (1 - T3.Discount)) DESC LIMIT 1