Look outside and try to determine if in fact a cable has broken. When one of my retraction cables broke, I was able to use a floor jack and a 2x4 to slightly lift the corner of the slides broken cable and then slowly retract the slide while my son guided the floor jack. Fortunately, we were parked on asphalt which facilitated the use of the floor jack.
The motor and cables can be accessed inside your unit. At the top of the slide there should be a decorative piece (wood trim) that can easily be removed. Mine was attached with velcro.
If a cable is broken, that is a whole different story. Due a search on this site. Wish you the best.
Ray