Thanks for the extra pictures. Airframe is trashed, retracts twisted and broken, engine rusty on outside so probably had rust inside. You were taken advantage of if you really got this for a $500 debt. The airframe has little value to anyone who sees all the pictures. The engine needs taken apart and examined. The radio most likely is ok but needs examined to be sure. Even if parted out there is no way you can get $500 unless you intend to  take advantage of someone. Take it back and get your $500 or part it out for a couple hundred. Just my honest assessment of the photos you sent me.