How to detect message that i send from one device to another with bluetoth connect

I want to send message from one device to another, i send and Toast show my message. I try to do:

if(message.equals("mute")){
                if(IsAudioOn){
                    IsAudioOn = false;
                    amanager.setStreamMute(AudioManager.STREAM_MUSIC, false); // for unmute

                }else{
                    IsAudioOn = true;
                    amanager.setStreamMute(AudioManager.STREAM_MUSIC, true);  //for mute
                }

for making instructions for device what he should do when he gets a typical message, but this didn't work,

Here are some of my methods from one device from which I try to control another:

public void sendMessage(String message) {
    if (bBluetooth) {
        bt.send(message, true);
    } else {
        wiFiP2pService.sendData(message);
    }
}

This works, I send the string MESSAGE and it shows on another device in TOAST method.

Here is my dataReceiver is on second device

bt.setOnDataReceivedListener(new BluetoothSPP.OnDataReceivedListener() {
        public void onDataReceived(byte[] data, String message) {
            showToastMessage(message, 300);
            AudioManager amanager=(AudioManager)getSystemService(Context.AUDIO_SERVICE);
            if(message.equals("MUTE")){
                if(IsAudioOn){
                    IsAudioOn = false;
                    amanager.setStreamMute(AudioManager.STREAM_MUSIC, false); // for unmute

                }else{
                    IsAudioOn = true;
                    amanager.setStreamMute(AudioManager.STREAM_MUSIC, true);  //for mute
                }
            }else if(message.equals("VOLUME DOWN")){
                amanager.setStreamVolume(
                        AudioManager.STREAM_MUSIC,
                        amanager.getStreamMaxVolume(AudioManager.STREAM_MUSIC),
                        0);
            }
        }
    });

as u see I try to detect like

message.equals("string")

but this does not work, Any help appreciated..

As per doc, setStreamMute -

This method should only be used by applications that replace the platform-wide management of audio settings or the main telephony application.

If you need to mute all sound on device, please take a look on possible solutions for that problem.