How to Send message to mobile no using c#

c# Code:

string ContactNo = "8343094272"; // to mobile no

                string MessageText = "Welcome to Softtechsolving"; // your message

                string strUrl = string.Format("http://api.mVaayoo.com/mvaayooapi/MessageCompose?user=softtechsolving@gmail.com:soft@123&senderID=TEST SMS&receipientno={0}&msgtxt={1}&state=4", ContactNo, MessageText);

                WebRequest request = HttpWebRequest.Create(strUrl);

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();

                Stream s = (Stream)response.GetResponseStream();

                StreamReader readStream = new StreamReader(s);

                string dataString = readStream.ReadToEnd();

                response.Close();

                s.Close();

                readStream.Close();

Namespace:

add this namespace to namespace area...

using System;

using System.Collections;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Net;

using System.IO;

using System.Data.SqlClient;