if/if else/else

I'm new to C# and have the following problem.

A program to calculate the duty to be paid on a vehicle. The user enters the type of car(there are 3 types), length of licence(6 or 12 months) and emission band (5 types) and the program prints out the cost of the license:

my code works perfectly as long as I choose 6 months licence length.

please help me understand what mistake I've made, thank you.

static void Main(string[] args)
    {
        bool check;
        int car, length;
        double rate = 0;
        string band = "";


        Console.WriteLine("{0,-12} {1,-12} {2,-12}", "Diesel Car", "Petrol Car", "Alt. Fuel Car");
        Console.WriteLine("{0,-12} {1,-12} {2,-12}", "TC 49", "TC 48", "TC 59");

        Console.WriteLine("Enter Car Type (TC #): ");
        check = int.TryParse(Console.ReadLine(), out car);
        if (check)
        {
            if (car == 49)
            {

                    Console.WriteLine("Enter Licience length in months(6 or 12)");
                    length = int.Parse(Console.ReadLine());
                    if (length == 6)
                    {
                        Console.WriteLine("Enter Emission Band (AA, A, B, C, D): ");
                        band = Console.ReadLine();
                        if (band == "AA")
                        {
                            rate = 44;
                        }
                        else if (band == "A")
                        {
                            rate = 60.5;
                        }
                        else if (band == "B")
                        {
                            rate = 71.5;
                        }
                        else if (band == "C")
                        {
                            rate = 82.5;
                        }
                        else if (band == "D")
                        {
                            rate = 88;
                        }
                        else
                            Console.WriteLine("ERROR"); //error for band != AA,A,B,C or D

                    }
                    else if (length == 12)
                    {
                        if (band == "AA")
                        {
                            rate = 80;
                        }
                        else if (band == "A")
                        {
                            rate = 110;
                        }
                        else if (band == "B")
                        {
                            rate = 130;
                        }
                        else if (band == "C")
                        {
                            rate = 150;
                        }
                        else if (band == "D")
                        {
                            rate = 160;
                        }
                        else
                            Console.WriteLine("ERROR"); //error for band != AA,A,B,C or D 
                    }
                    else
                        Console.WriteLine("ERROR"); // error for length != 6 or 12

            }
            else if (car == 48)
            {
                Console.WriteLine("Enter Licience length in months(6 or 12)");
                length = int.Parse(Console.ReadLine());
                if (length == 6)
                {
                    Console.WriteLine("Enter Emission Band (AA, A, B, C, D): ");
                    band = Console.ReadLine();
                    if (band == "AA")
                    {
                        rate = 38.5;
                    }
                    else if (band == "A")
                    {
                        rate = 55;
                    }
                    else if (band == "B")
                    {
                        rate = 66;
                    }
                    else if (band == "C")
                    {
                        rate = 77;
                    }
                    else if (band == "D")
                    {
                        rate = 85.25;
                    }
                    else
                        Console.WriteLine("ERROR"); //error for band != AA,A,B,C or D

                }
                else if (length == 12)
                {
                    if (band == "AA")
                    {
                        rate = 70;
                    }
                    else if (band == "A")
                    {
                        rate = 100;
                    }
                    else if (band == "B")
                    {
                        rate = 120;
                    }
                    else if (band == "C")
                    {
                        rate = 140;
                    }
                    else if (band == "D")
                    {
                        rate = 155;
                    }
                    else
                        Console.WriteLine("ERROR"); //error for band != AA,A,B,C or D 
                }
                else
                    Console.WriteLine("ERROR"); // error for length != 6 or 12
            }
            else if (car == 59)
            {
                Console.WriteLine("Enter Licience length in months(6 or 12)");
                length = int.Parse(Console.ReadLine());
                if (length == 6)
                {
                    Console.WriteLine("Enter Emission Band (AA, A, B, C, D): ");
                    band = Console.ReadLine();
                    if (band == "AA")
                    {
                        rate = 33;
                    }
                    else if (band == "A")
                    {
                        rate = 49.5;
                    }
                    else if (band == "B")
                    {
                        rate = 60.5;
                    }
                    else if (band == "C")
                    {
                        rate = 71.5;
                    }
                    else if (band == "D")
                    {
                        rate = 82.5;
                    }
                    else
                        Console.WriteLine("ERROR"); //error for band != AA,A,B,C or D

                }
                else if (length == 12)
                {
                    if (band == "AA")
                    {
                        rate = 60;
                    }
                    else if (band == "A")
                    {
                        rate = 90;
                    }
                    else if (band == "B")
                    {
                        rate = 110;
                    }
                    else if (band == "C")
                    {
                        rate = 130;
                    }
                    else if (band == "D")
                    {
                        rate = 150;
                    }
                    else
                        Console.WriteLine("ERROR"); //error for band != AA,A,B,C or D 
                }
                else
                    Console.WriteLine("ERROR"); // error for length != 6 or 12
            }
            else
                Console.WriteLine("ERROR"); // error for car number != 48,49 or 59
        }
        else
            Console.WriteLine("ERROR"); //error for car num != int
        Console.WriteLine(rate);
    }