Я не могу заставить расчеты работать. Помогите пожалуйста

 class Program
    {


        static void Main(string[] args)
        {
            string customerName = "", state = "";
            int quantity = 0;
            double price = 0, sales = 0, tax = 0;

            Console.WriteLine("\n\nWelcome to the Sales Tax Calculator");

            Console.Write("\n\nPlease enter in the customer name:  ");
            customerName = Console.ReadLine();
            Console.Write("\n\nPlease enter in the State (NY / NJ / FL):  ");
            state = Console.ReadLine();
            Console.Write("\n\nPlease enter in the number of items purchased:  ");
            quantity = Convert.ToInt32(Console.ReadLine());
            Console.Write("\n\nPlease enter in the unit price of the item:  ");
            price = Convert.ToDouble(Console.ReadLine());



            sales = ComputeTotal(quantity, price);

            tax = ComputeTax(sales, state);

            Console.WriteLine(customerName + " your total sales are:  ");

            Console.WriteLine("Your total with taxes is:  " + tax);


            Console.ReadLine();
            
        }
        public static double ComputeTotal(int quantity, double price)
        {
            return (quantity * price);
        }

        public static double ComputeTax(double sales, string state)
        {
            double taxAmt = 0;

            if (state == "NY")
                taxAmt = sales * .04;
            else if (state == "NJ")
                taxAmt = sales * .07;
            else if (state == "FL")
                taxAmt = sales * .06;

            return taxAmt;


        }
    }
}