If Else Troubles (C#)

I have an issue with my if else statement to where it will only display the else output and not the if output.

     default:
                if (GradeVar >= 10)
                {

                    Console.WriteLine("That grade is a perfect score. Well done!");


                }
                else
                {
                    Console.WriteLine("That grade is not passing.");
                }
                break;


        }
        Console.ReadLine();
        }


    }
}

Here's the specific code I am talking about; its for a program to display certain messages for grades