Please help me with the task: Encode the message

Hello, I’m working on this task:

We like ciphers at the resistance base. For internal communication, we use a substitutional cipher. The idea is very simple: every letter in the incoming message is substituted with a different symbol. Your task is to partially encode a string message given to your program as an input and output the encoded message. Leave all letters except for the following:

  • F and f: replace with !
  • G and g: replace with @
  • T and t: replace with #
  • H and h: replace with $
  • Y and y: replace with %
  • B and b: replace with ^
    For Example:
    >After seeinG my dark Future, I can’t continue living in the Boring past.
    A!#er seein@ m% dark !u#ure, I can’# con#inue livin@ in #$e ^orin@ pas#.

Here is my code:


namespace SwitchStatement
{
   class SubstitutionCipher
   {
       static void Main()
       {
           var message = Console.ReadLine();
           //var lowerMessage = message;
           //char.ToLower(lowerMessage);
           for (int i = 0; i < message.Length; i++)
           {
               
               switch (message[i])
               {
                   case 'f':
                       Console.Write('!'); 
                       break;                       
                   case 'g':
                       Console.Write('@');
                       break;
                   case 't':
                       Console.Write('#');
                       break;
                   case 'h':
                       Console.Write('$');
                       break;
                   case 'y':
                       Console.Write('%');
                       break;
                   case 'b':
                       Console.Write('^');  
                       break;             
                   default:
                       Console.Write(message[i]);
                       break; 
               }
               
           }
       }
   }
      
}

Can anyone please help me to solve it?