Get JapanPost "〒 (郵便記号, yūbin kigō)" delivery status using windows console app

JapanPostDeliveryStatus.cs

/*
* Author : julius limson
* Description : Get JapanPost "〒 (郵便記号, yūbin kigō)" delivery status 
* Parameter : args[0] = Tracking Number
* Output: (delivered, returned to sender, not delivered) and dates. 
* usage : in cmd 
   ProjLocation> Projectname.exe <trackingnumber>  
   
*/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Text.RegularExpressions;

namespace Japanpost_deliverystatus
{
    class Program
    {
        static void Main(string[] args)
        {
            
            string tracking_number = Regex.Replace(args[0], "[^0-9_.]+", "", RegexOptions.Compiled);
            var values = new List<KeyValuePair<string, string>>
                    {
                        new KeyValuePair<string, string>("requestNo1", tracking_number),
                        new KeyValuePair<string, string>("search.x", "0"),
                        new KeyValuePair<string, string>("search.y", "0"),
                        new KeyValuePair<string, string>("search", "Tracking+start"),
                        new KeyValuePair<string, string>("locale", "en"),
                        new KeyValuePair<string, string>("startingUrlPatten", "")
                    };
            var client = new HttpClient();
            var requestContent = new FormUrlEncodedContent(values);

            var response = client.PostAsync("https://trackings.post.japanpost.jp/services/srv/search/", requestContent).Result;
            var content = response.Content.ReadAsStringAsync().Result;

           
            if (response.Content.ReadAsStringAsync().Result.Contains("Final delivery")) {
                Console.Write("delivered - {0}\n", tracking_number);

                var arr = Regex.Matches(content, @"\d{2}/\d{2}/\d{4}").Cast<Match>()
                   .Select(m => m.Value)
                   .ToArray();
            
                string sent_date = arr[0];
                string received_date = arr[arr.Count() - 1];
                Console.WriteLine("Fulfill on {0} Delivered on {1}", sent_date, received_date);
            }
            else
            {
                if (response.Content.ReadAsStringAsync().Result.Contains("Returned to sender"))
                {
                    Console.Write("Returned to sender - {0} \n", tracking_number);
                    var arr = Regex.Matches(content, @"\d{2}/\d{2}/\d{4}").Cast<Match>()
                                .Select(m => m.Value)
                                .ToArray();

                    string sent_date = arr[0];
                    string returned_date = arr[arr.Count() - 1];
                    Console.WriteLine("Fulfill on {0} Returned on {1}", sent_date, returned_date);
                }
                else {
                    Console.Write("\"{0}\" - not delivered\n", tracking_number);
                }                
            }
        }
    }
}