Phone wont turn on after replaced volume/mute flex cable. Plz help.

I replaced the complete part for the volume and mute button thinking it would work fine but now the phone is umresponsive. It is seen on itunes and i restored it but still nothing on the lcd. Eve put the button back to original and tried a different lcd did the power and homebutton hold for 30 seconds and no response. Does anyone have any advice im in a pinch