Hi everyone!
To help you intergrate our getting CID API (by Auto Call) into your system, we will update docs and help at here. We will use C# for sample code, then you can convert to your language.
This is our API:
https://kichhoat24h.com/user-api/get-cid?iid=[iid]&price=[price]&token=[token_id]&send_to_email=[send_to_email]&callback_url=[callback_url]

iid: this is your Installation ID
price: this is price you ready to pay for that installation ID
token: this is your token ID, you can login the website and get it at https://kichhoat24h.com/apis
send_to_email: you can set any email at here, then when auto call completed, we will send IID/CID to this email by using our email system. You can use this for debugging or if you don’t have any SMTP email service.
callback_url: if you set it, when auto call completed, we will call this url and post iid and cid to this url (using POST method).

This is code from our server:

                   var request = (HttpWebRequest)WebRequest.Create(callback_url);

                    var postData = "iid=" + Uri.EscapeDataString(iid);

                    postData += "&cid=" + Uri.EscapeDataString(cid);

                    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();

send_to_email and callback_url are optional options, you can skip them.

We will discuss about the API response now. This is all response cases:

{"success":true,"cid":null,"response_message":"We are calling to get CID for you.","error_message":null}

{"success":true,"cid":null,"response_message":"We are calling to get CID for you and will send it to your email soon.","error_message":null}

{"success":true,"cid":null,"response_message":"We are calling for this IID, please wait for it complete.","error_message":null}

{"success":true,"cid":null,"response_message":"Dead Key.","error_message":null}

{"success":true,"cid":null,"response_message":"Key Blocked.","error_message":null}

{"success":true,"cid":null,"response_message":"Fake Key.","error_message":null}

{"success":true,"cid":null,"response_message":"Need to call MS Support.","error_message":null}

{"success":true,"cid":null,"response_message":"Wrong IID.","error_message":null}

{"success":true,"cid":"426296483130829081064403777482905722580616","response_message":"426296483130829081064403777482905722580616","error_message":null}

{"success":false,"cid":null,"response_message":null,"error_message":"Invalid IID Length!"}

{"success":false,"cid":null,"response_message":null,"error_message":"Server busy, please try again later"}

{"success":false,"cid":null,"response_message":null,"error_message":"You have reached maximum calling IIDs, please wait for all complete"}

{"success":false,"cid":null,"response_message":null,"error_message":"Please add credit to using Auto Call."}

{"success":false,"cid":null,"response_message":null,"error_message":"Invalid syntax or token!"}

And this is the sample code to get cid from API:
        public static string GetCID(string iid, float price, string token)
        {
            string cid = "";

            while (true)
            {
                try
                {
                    var request = (HttpWebRequest)WebRequest.Create("https://kichhoat24h.com/user-api/get-cid");

                    var postData = "iid=" + Uri.EscapeDataString(iid);
                    postData += "&price=" + Uri.EscapeDataString(price.ToString());
                    postData += "&token=" + Uri.EscapeDataString(token);
                    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();

                    string res = new StreamReader(response.GetResponseStream()).ReadToEnd();

                    dynamic dRes = JsonConverter.DeserializeObject<dynamic>(res);
                    if (dRes["success"] == false)
                    {
                        Console.WriteLine(dRes["error_message"]);
                        break;
                    }
                    else if (dRes["cid"] != null)
                    {
                        cid = dRes["cid"];
                    }
                    else if (!dRes["response_message"].Contains("We are calling"))
                    {
                        cid = dRes["response_message"];
                    }
                }
                catch (Exception e1)
                {
                    break;
                };

                Thread.Sleep(1000);
            }

            return cid;
        }

Hope all above information helpful for you. Thank you very much!