ok ive got a bit of a problem with the curtain/screen (which ever) that hides the cargo in the rear of the car. something must've broke because it doesn't retract when i attempt to roll the screen back in, or it droops wen i hav it on... is there any way to fix this or do i have do i hav to buy a whole new screen? if i gota buy a new screen how much will this set me back?