When I want to raise or lower the volume of the hands-free Kit it changes the song.

If you make short supports on the volume buttons of your hands-free kit This will change the music. For example, if you press the volume (-) button briefly, you will read the previous song and if you do a short press on the volume (+) you will skip to the next song. To increase or decrease the volume you need to make long supports (about 2 seconds).