How to get communication response using MQTT

I'm developing an application which uses the MQTT communication protocol, where my system sends a command to a certain device, my machine is receiving the command and changing the status. The problem is: how do I get feedback from my device? Because my system needs to get back if the equipment has changed its status and what the current status is so that it will be displayed on my system.

My MQTT class' package business;

import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

public class Mqtt implements MqttCallback {

private static Mqtt INSTANCE;

MqttClient client;
//String ipPatchPanel;
//String mensagem = "D" + "numeroPorta" + "comando";
String topico = "Stream";

private Mqtt() throws MqttException {
    client = new MqttClient("tcp://192.168.1.105:1883", "Enviando...");
    client.connect();
    client.setCallback(this);
}

//Singleton
public static Mqtt getInstance() throws MqttException {
    if (INSTANCE == null) {
        return new Mqtt();
    } else {
        return INSTANCE;
    }
}

public void comandoMqtt(String ip, String porta, String comando) {
    try {
        String comandos = ip + "&" + porta + "&" + comando; // string que recebe e concatena três parâmetros recebidos na função
        client.subscribe(topico);//tópico de subscrição é o mesmo valor do IP
        MqttMessage message = new MqttMessage();
        message.setPayload(comandos.getBytes());
        client.publish(topico, message);//tópico onde publica é o mesmo valor do ip e o outro parâmetro é a mensagem
    } catch (MqttException e) {
        e.printStackTrace();
    }
}

@Override
public void connectionLost(Throwable cause) {
    // TODO Auto-generated method stub

}

@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
    System.out.println(message);
}

@Override
public void deliveryComplete(IMqttDeliveryToken token) {
    // TODO Auto-generated method stub

}

}

E meu MQTT-Arduino: #include     #include     #include

// Update these with values suitable for your network.
byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
IPAddress ip(192, 168, 1, 122);
IPAddress server(192, 168, 1, 117);
char mensagem;
int ledAmarelo = 3;
int ledVerde = 4;

void callback(char* topic, byte* payload, unsigned int length) {
Serial.print("Message arrived [");
Serial.print(topic);
Serial.print("] ");
for (int i=0;i<length;i++) {
mensagem = (char)payload[i];
Serial.print((char)payload[i]);

if(mensagem == "ativoAmarelo"){
  Serial.println("Led Amarelo Ativado");
  digitalWrite(ledAmarelo, HIGH);
}
if(mensagem == "ativoVerde"){
  Serial.println("Led Verde Ativado");
  digitalWrite(ledVerde, HIGH);
}
}
Serial.println();
}

EthernetClient ethClient;
PubSubClient client(ethClient);

void reconnect() {
// Loop until we're reconnected
while (!client.connected()) {
Serial.print("Attempting MQTT connection...");
// Attempt to connect
if (client.connect("arduinoClient")) {
  Serial.println("connected");
  // Once connected, publish an announcement...
  client.publish("outTopic","hello world");
  // ... and resubscribe
  client.subscribe("inTopic");

} else {
  Serial.print("failed, rc=");
  Serial.print(client.state());
  Serial.println(" try again in 5 seconds");
  // Wait 5 seconds before retrying
  delay(5000);
}
}
}

void setup()
{
 Serial.begin(57600);

 client.setServer(server, 1883);
 client.setCallback(callback);

 Ethernet.begin(mac, ip);
 // Allow the hardware to sort itself out
 delay(1500);
}

void loop()
{
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
}

'

In the console I see the sending taking the ip of the equipment and the command corresponding to the button clicked in the web system.