Отправка смс через сервис Smsified.com

using System;
using System.Text;
using System.Net;
using System.IO;

namespace smsifiedexample
{
 class MainClass
 {  
  public static void Main (string[] args)
  {
   // SMSified API endpoint.
   string webTarget = "https://api.smsified.com/v1/smsmessaging/outbound/{0}/requests";

   // Parameters to send with API request.
   string webPost = "address={0}&message={1}";

   // SMSified credentials.
   string userName = "";
   string password = "";
   string senderNumber = "";

   // Create new HTTP request.
   string url = String.Format(webTarget, senderNumber);
   HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
   req.Method = "POST";
   req.ContentType =  "application/x-www-form-urlencoded";
   byte[] postData = Encoding.ASCII.GetBytes(String.Format(webPost, "14075551212", "This is a test from C#"));
   req.ContentLength = postData.Length;

   // Set HTTP authorization header.
   string authInfo = userName + ":" + password;
   authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
   req.Headers["Authorization"] = "Basic " + authInfo;

   // Send HTTP request.
   Stream PostStream = req.GetRequestStream();
   PostStream.Write(postData, 0, postData.Length);   
   HttpWebResponse res = (HttpWebResponse)req.GetResponse();

   // Evaluate result of HTTP request.
   if(res.StatusCode == HttpStatusCode.Created) {
    Console.WriteLine("SMS message has been sent.");
   }
   else
   {
    Console.WriteLine(
                        "ERROR: There was a problem sending your messaging.");
   }
  }  
 }
}