Starbucks C#

using System;

namespace Starbucks
{
class Program
{
static void Main(string[] args)
{
string seleccion, op, CafeSelec, FrapSelec, PostreSelec;double Cafe = 0, Mediano = 0, Grande = 0, Frapuccino = 0, Vainilla = 0, Moka = 0, Postres = 0, Pay = 0, Pastel = 0, Total = 0, Descuento1 = 0, Descuento2 = 0, Total1 = 0, Total2 = 0, Total3 = 0;Console.WriteLine("Bienvenido a Starbucks");
do
{
Console.WriteLine("Cual producto desea?: ");
Console.WriteLine("Cafe");Console.WriteLine("Frapuccino");
Console.WriteLine("Postres");
seleccion = Console.ReadLine();
switch (seleccion)
{case "Cafe":
Cafe++;
Console.WriteLine("Mediano: "); Console.WriteLine("$20");
Console.WriteLine("Grande:"); Console.WriteLine("$35");
CafeSelec = Console.ReadLine();
switch (CafeSelec)
{
case"Mediano":
Console.WriteLine("Cuantos desea?: ");
Mediano = 20 * double.Parse(Console.ReadLine());
break;case "Grande":
Console.WriteLine("Cuantos desea?: ");
Grande = 35 * double.Parse(Console.ReadLine());break;
}
break;
case "Frapuccino":
Frapuccino++;Console.WriteLine("Vainilla: "); Console.WriteLine("$40");
Console.WriteLine("Moka: "); Console.WriteLine("$45");
FrapSelec = Console.ReadLine();...