リストを更新してもNotification（通知）が更新されない

リスト（文字列）の内容をNotificationを使って通知しようとしています
最初に通知した際は想定通りに動くのですがリストを削除、追加して通知しようとすると更新前のの前回の内容で通知されてしまいます
更新されたリストの内容で通知したいです。
リスト自体は中身を取得して確認していますが問題無いようです
何が原因なのでしょうか？

以下が簡略化したソースになります

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private List<String> listName=new ArrayList<>();
    private int count=3;
    private String s;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        for (int i=0;i<3;i++){
            listName.add(String.valueOf(i));
        }

        s="list1="+listName.get(0)+"     list2="+listName.get(1)+"     list3="+listName.get(2);

        TextView textView=findViewById(R.id.textView);
        textView.setText(s);
        Button button=findViewById(R.id.button);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                listName.remove(0);
                listName.add(2,String.valueOf(count));
                count++;
                s="list1="+listName.get(0)+"     list2="+listName.get(1)+"     list3="+listName.get(2);
                TextView textView=findViewById(R.id.textView);
                textView.setText(s);
            }
        });

        Button button1=findViewById(R.id.button2);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                setAlarm();
            }
        });



    }

    private void setAlarm(){

        for(int i=0;i<listName.size();i++){

            Intent intent = new Intent(getApplicationContext(),
                    AlarmBroadcastReceiver.class);
            intent.putExtra("intent",listName.get(i));
            intent.putExtra("req",i);

            PendingIntent pending = PendingIntent.getBroadcast(
                    getApplicationContext(), i, intent, 0);

            AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
            if(am != null) {
                am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+(i+1)*10000, pending);
            }
        }

        Toast.makeText(getApplicationContext(),
                "set Alarm", Toast.LENGTH_SHORT).show();
    }
}



import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.media.RingtoneManager;
import android.net.Uri;
import android.support.v4.app.NotificationCompat;
import android.support.v4.app.NotificationManagerCompat;
import android.widget.Toast;

public class AlarmBroadcastReceiver extends BroadcastReceiver {

    public void onReceive(Context context, Intent intent) {
        String s=intent.getStringExtra("intent");
        int req=intent.getIntExtra("req",0);

        String title = context.getString(R.string.app_name);
        String message ="『" +s+"』からの通知";

        Intent ni = new Intent(context,MainActivity.class);

        PendingIntent pendingIntent =
                PendingIntent.getActivity(context, req, ni,
                        PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT);


        NotificationManager notificationManager =
                (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);


        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            NotificationChannel channel;
            channel = new NotificationChannel(
                    "def", title , NotificationManager.IMPORTANCE_DEFAULT);

            channel.setDescription(message);
            channel.enableVibration(true);
            channel.canShowBadge();
            channel.enableLights(true);
            channel.setLightColor(Color.BLUE);
            channel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);
            channel.setSound(defaultSoundUri, null);
            channel.setShowBadge(true);

            if(notificationManager != null){
                notificationManager.createNotificationChannel(channel);

                Notification notification = new Notification.Builder(context, "def")
                        .setContentTitle(title)
                        .setSmallIcon(android.R.drawable.ic_lock_idle_alarm)
                        .setContentText(message)
                        .setAutoCancel(true)
                        .setContentIntent(pendingIntent)
                        .setTicker(message)
                        .setWhen(System.currentTimeMillis())
                        .build();

                notificationManager.notify(R.string.app_name, notification);
                Toast.makeText(context, message, Toast.LENGTH_LONG).show();

            }
        }else {
            NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
            builder.setSmallIcon(android.R.drawable.ic_lock_idle_alarm);

            builder.setContentIntent(pendingIntent);
            builder.setContentTitle(title);
            builder.setContentText(message);
            builder.setTicker(message);
            builder.setAutoCancel(true);
            long[] vibrate_ptn = {0, 150, 300, 150};
            builder.setVibrate(vibrate_ptn);
            NotificationManagerCompat manager = NotificationManagerCompat.from(context);
            manager.notify(req, builder.build());
            Toast.makeText(context, message, Toast.LENGTH_LONG).show();

        }


    }
}