Ringtone application, registers an mp3 but doesn't play it

Question

As a personal project, I've been trying to make an app that lists the music in my device and you can set any of this the default ringtone.

First, I get all the music in my device.

 public void getSongList() {
    ContentResolver musicResolver = getContentResolver();
    musicUri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);

    Log.d("helena", "urimusic : "+musicUri);
    finalpath = musicUri.getEncodedPath();


    if(musicCursor!=null && musicCursor.moveToFirst()){
        //get columns
        int titleColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media.TITLE);
        int idColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media._ID);
        int artistColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media.ARTIST);

        //Log.d("helena",""+data);
        do {
            long thisId = musicCursor.getLong(idColumn);
            String thisTitle = musicCursor.getString(titleColumn);
            String thisArtist = musicCursor.getString(artistColumn);
            Song cancion = new Song(thisArtist,thisId,thisTitle);
            songList.add(cancion);
        }
        while (musicCursor.moveToNext());
    }
}

then, I show the titles in a ListView: when the user click on an element I call:

 public void setRingTone(int index){
    String path = this.finalpath; //got it from uri
    String songName = songList.get(index).getTitle();
    String artist = songList.get(index).getArtist();

        File k = new File(path, songName );

        Log.d("helena","song:"+songName +", path:"+path+", absolutepath:"+k.getAbsolutePath());

        ContentValues values = new ContentValues();
        values.put(MediaStore.MediaColumns.DATA, k.getAbsolutePath());
        values.put(MediaStore.MediaColumns.TITLE,songName );
        values.put(MediaStore.MediaColumns.MIME_TYPE, "audio/mpeg");
        values.put(MediaStore.Audio.Media.ARTIST, artist);
        values.put(MediaStore.Audio.Media.IS_RINGTONE, true);
        values.put(MediaStore.Audio.Media.IS_NOTIFICATION, false);
        values.put(MediaStore.Audio.Media.IS_ALARM, false);
        values.put(MediaStore.Audio.Media.IS_MUSIC, false);


    Uri uri = MediaStore.Audio.Media.getContentUriForPath(k.getAbsolutePath());
    getContentResolver().delete(uri, MediaStore.MediaColumns.DATA + "=\"" + k.getAbsolutePath() + "\"", null);
    Uri newUri = getContentResolver().insert(uri, values);
    RingtoneManager.setActualDefaultRingtoneUri(
            MainActivity.this,
            RingtoneManager.TYPE_RINGTONE,
            newUri
    );


    Toast.makeText(this,"ringtone changed",Toast.LENGTH_SHORT).show();
}

It shows the song name as the default ringtone, but doesn't make any sound in the systems>sounds>ringtone, and when I get a call, it plays the previous (default) ringtone.

Any advice?