Cord of balancing systen has been broken. i think balancing systen is at the top of the window, I removed couple of scews from the window top frame but could not remove the balancing spring. I have attached 4 pictures. one picture include plastic channels which goes on the side of the window. Other pictures show a hook with broken cord, black plastic channels. Need to know the replacement part and how to remove the broken balancing system.
Thank you,
Rashid