[Camr]

In order for the slide "box" to twist front to back, the floor of the slide would have to be lower at the front (pin box) end than the rear. Can you look under the slide to see if perhaps one of the rollers at the front end is missing? Or perhaps something wedged at the rear that would make the rear of the slide higher than the front. Judging by the photos, which can often be misleading, the only way to make the top edge of the front slide wall touch the wall opening would be to somehow twist the slide box counter clockwise.