Coil spring is sprung

One side of the window makes a clicking sound when you try to open or close the window. Window will not go all the way up, and even pushed up as far as it will go (only about halfway) it will sag down to only a couple of inches. On the track on the right side the spring/coil is visible in the window track. There are letters with indent circles next to the letters A, B,C,D,E,F down the center of the plastic. There is a larger number 3 embossed along front left side. There is nothin on the plastic of the shoe on this side but the right side has a 5A embossed in the plastic right above the shoe. I would truly appreciate any assistance you could provide in identifying the proper replacement and a quick 'how to' advice on how to get our window working back to to normal. This is amazing that this service exists. Thank you so much.