How do I get value of response parameter on my (response page) after made payment by buyer.

hi,
 
i am developing a web application in C#.

i want to get value of response parameter on my conformation (response page) after made payment by buyer using buyer account.

 i am currentlly using this code.

     protected void Page_Load(object sender, EventArgs e)
    {
 if (Request.Form["payment_status"] == "Completed")
        {
      //Create Entry to Database
      string receipt_id = Request.Form ["receipt_id"];
      string first_name = Request.Form["first_name"];
      string last_name = Request.Form["last_name"];
      string payer_email = Request.Form["payer_email"];
      string contact_phone = Request.Fo ...