无法取回任何东西，但默认构造函数给出的内容

我觉得我正在使用调试器，但仍然无法弄清楚这个问题。

我正在演练以下代码

namespace Taxes
{
public class Rates
{

    //A class constructor that assigns default values 
    public Rates()
    {
        incLimit = 30000;
        lowTaxRate = .15;
        highTaxRate = .28;
    }
    //A class constructor that takes three parameters to assign input values for limit, low rate and high rate.
    public Rates(int lim, double low, double high)
    {
        incLimit = lim;
        lowTaxRate = low;
        highTaxRate = high;
    }
    //  A CalculateTax method that takes an income parameter and computes the tax as follows:
    public int CalculateTax(int income)
    {
        //determine if the income is above or below the limit and calculate the tax owed based on the correct rate
        int taxOwed;
        if (income < incLimit)
            taxOwed = Convert.ToInt32(income * lowTaxRate); 
        else 
            taxOwed = Convert.ToInt32(income * highTaxRate);
        return taxOwed;
    }

} 
// The Taxpayer class is a comparable class
public class Taxpayer : IComparable
{
    //Use get and set accessors.
    private int taxOwed;
    string SSN
    { set; get; }
    int grossIncome
    { set; get; }
    int TaxOwed {
        get
        {
            return taxOwed;
        }
    }
    int IComparable.CompareTo(Object o)
    {
        int returnVal;
        Taxpayer temp = (Taxpayer)o;
        if (this.taxOwed > temp.taxOwed)
            returnVal = 1;
        else if (this.taxOwed < temp.taxOwed)
            returnVal = -1;
        else returnVal = 0;
        return returnVal;
    }  
    public static Rates GetRates()
    {
        //  Local method data members for income limit, low rate and high rate.
        int incLimit;
        double lowRate;
        double highRate;
        string userInput;
        //Rates myRates = new Rates(incLimit, lowRate, highRate);
        //Rates rates = new Rates();
        //  Prompt the user to enter a selection for either default settings or user input of settings.
        Console.Write("Would you like the default values (D) or would you like to enter the values (E)?:  ");
        // if they want the default values or enter their own
        userInput = (Console.ReadLine());
        if (userInput == "D" || userInput == "d")
        {
            Rates myRates = new Rates();
            return myRates;
            //Rates.Rates();
            //rates.CalculateTax(incLimit);
        }
        else if (userInput == "E" || userInput == "e")
        {
            Console.Write("Please enter the income limit: ");
            incLimit = Convert.ToInt32(Console.ReadLine());
            Console.Write("Please enter the low rate: ");
            lowRate = Convert.ToDouble(Console.ReadLine());
            Console.Write("Please enter the high rate: ");
            highRate = Convert.ToDouble(Console.ReadLine());

            Rates myRates = new Rates(incLimit, lowRate, highRate);
            return myRates;
            //rates.CalculateTax(incLimit);
        }
        else return null;
    }
    static void Main(string[] args)
    {
        Taxpayer[] taxArray = new Taxpayer[5];
        //Rates taxRates = new Rates();
        //  Implement a for-loop that will prompt the user to enter the Social Security Number and gross income.
        for (int x = 0; x < taxArray.Length; ++x)
        {
            taxArray[x] = new Taxpayer();
            Console.Write("Please enter the Social Security Number for taxpayer {0}:  ", x + 1);
            taxArray[x].SSN = Console.ReadLine();
            Console.Write("Please enter the gross income for taxpayer {0}:  ", x + 1);
            taxArray[x].grossIncome = Convert.ToInt32(Console.ReadLine());
            //taxArray[x].taxOwed = taxRates.CalculateTax(taxArray[x].grossIncome);
        }
        Rates myRate = Taxpayer.GetRates();
        //Taxpayer.GetRates();
        //  Implement a for-loop that will display each object as formatted taxpayer SSN, income and calculated tax.
        for (int i = 0; i < taxArray.Length; ++i)
        {
            Console.WriteLine("Taxpayer # {0} SSN: {1}, Income is {2:c}, Tax is {3:c}", i + 1, taxArray[i].SSN, taxArray[i].grossIncome, myRate.CalculateTax(taxArray[i].grossIncome));//taxArray[i].taxOwed);
        } 
        //  Implement a for-loop that will sort the five objects in order by the amount of tax owed 
        Array.Sort(taxArray);
        Console.WriteLine("Sorted by tax owed");
        for (int i = 0; i < taxArray.Length; ++i)
        {
            //double taxes = myTax.CalculateTax(taxArray[i].grossIncome);
            Console.WriteLine("Taxpayer # {0} SSN: {1}, Income is {2:c}, Tax is {3:c}", i + 1, taxArray[i].SSN, taxArray[i].grossIncome, myRate.CalculateTax(taxArray[i].grossIncome));
        }
    }  
} 
} 

我已经解决了所有问题，除了由于某种原因，排序没有按欠税金额排序。