What's the brand name on the control panel? They most likely have a website and probably a PDF copy of the manual.
Do you hear the pump operating when you try to retract the jack? If it's a hydraulic piston jack, you can try cleaning the shiny piston with Silicon spray or WD-40. If the pump is running but no movement, you might try lifting the jack with a 2x4 as a lever to get it moving.
If it's an electric jack, you'll have to consult the manual to see if it can be retracted with a socket or a drill.
Linear Mode
