Identifying Clients

Hello Everybody:

I have created a multithreaded client server application...The server can received 50 client connections by creating new threads..The client uses there name and phone number as parameters to connect to the server...
Now I want to send the information back to the same client
from the server. My problem is identifying the correct client and sending the information to the correct client.
I am identifying the client by using the GetHashCode method
which will be generated by the name and phone number the client uses to login to the server.

I am storing the information in a hashtable and retriving the information and sending the information.. How it does not seem to work..

Pls guide...
try
{

if ((table.ContainsKey(txtOutput.Text)==true))

{

Object objData = txtDataTx.Text;
byte[] byData = System.Text.Encoding.ASCII.GetBytes(objData.ToString ());

m_socWorker.Send (byData);
}
}
catch(SocketException se)
{
MessageBox.Show (se.Message );
}
statuslabel.Text="";
txtDataTx.Text="";