iPod nano 6g headphone jack repair

[Haze]

hi,

my iPod nano 6g headphone jack broke about 2 months ago.
The problem at first only was that when I take the headphone plug out of the jack the music would not stop playing, which would result in an empty battery the next day.
I continued using the iPod till several weeks ago the button to turn up the music broke as well.
I checked the local store for repair cost which would have been 80 Euros so i got a replacement jack on amazon.
The headphone jack is attached to the volume buttons including power button.

Now after replacing the jack, the buttons work but the music "quality" if u can call it that:) is terrible well actually not evan there.
Where ever i plug my ipod into it sounds like the speakers are blown, where as they work with other devices.
Headphones as well sound blown and fuzzy.

What do you think could have gone wrong?

I already replaced the isolation tape in the iPod.

Could I have broken some cables?

im addicted to music so pleaz help me:D