public string sendSMS(string usernumber, string OTPCode)
    {
        String message = HttpUtility.UrlEncode("This is your OTP : " + OTPCode + ". This will expire in 30 seconds.");
        using (var wb = new WebClient())
        {
            byte[] response = wb.UploadValues("https://api.txtlocal.com/send/", new NameValueCollection()
                {
                {"apikey" , "x8rWcDHLA5k-fFTonLa0MTvLqhe1Y4YqMi9LV2YbkU"},
                {"numbers" , usernumber},
                {"message" , message},
                {"sender" , "OTP"}
                });
            string result = Encoding.UTF8.GetString(response);
            return result;
        }
    }