public confirmationStatus Send(string phoneNumber, string text)
{

    messages_send model = new messages_send() { contacts = new List<string>() { phoneNumber }, text=text };
    string url = this.setupUrl();
    string dataToSend = new JavaScriptSerializer().Serialize(model);

    var cli = new WebClient();
    cli.Headers[HttpRequestHeader.ContentType] = "application/json";
    string response = cli.UploadString(url, dataToSend);

    return new JavaScriptSerializer().Deserialize<confirmationStatus>(response);

}

POST https://api.***.com/v1/messages? HTTP/1.1
Content-Type: application/json
Host: api.**.com
Content-Length: 1061
Expect: 100-continue
Connection: Keep-Alive

{"contacts":["+1*****9"],"text":"**??HME??????** John,??? 01-01-0001 ???? 12:00 AM ? 12:00 AM? ????????????????????: Link: https://www.****.com/timesheets/?v=0 .Text STOP                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     "}