AZcaptcha C# recaptcha v2 resolver code

public string SendRecaptchav2Request()
        {
            //POST
            try
            {
                System.Net.ServicePointManager.Expect100Continue = false;
                var request = (HttpWebRequest)WebRequest.Create("http://azcaptcha.com/in.php");

                var postData = "key=AZcaptcha_API_KEY&method=userrecaptcha&googlekey=GOOGLE_KEY";//&pageurl=yourpageurl"; ;
                var data = Encoding.ASCII.GetBytes(postData);

                request.Method = "POST";

                request.ContentType = "application/x-www-form-urlencoded";
                request.ContentLength = data.Length;

                using (var stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }

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

                var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

                //  GET
                if (responseString.Contains("OK|"))
                {
                    return responseString.Substring(0, 3);
                }
                else
                {
                    return "Error";
                }
            }
            catch (Exception e)
            {
                string tt = e.Message;
                return tt;
            }

        }