What happened to the scooter just before it stopped working, under what conditions? That may help diagnose the problem.
Does the motor even attempt to spin in response to throttle command, when the wheels are offground? Any movement or sound at all?
If it's actually the controller having "lost" programming, that would mean that someone changed settings in it to non-working ones, or replaced the controller with an unprogrammed one (wasn't setup yet or wasn't setup for this system), or replaced the display with one that is expecting other answers back from the controller when queried. In either case, without the software and cabling to fix this, the exisitng controller/display set problem couldn't be corrected.
If the controller was made for the OEM company, then there won't likely be identical spare parts out there***, and you'd have to replace the controller and display as a set with a set that is capable of the same things this one was:
--same battery voltage range (for HVC, LVC)
--same battery current limit
--same phase current limit
You'll also want to be sure it has the same feature set to match how this controller operated, if you want it to behave like it did before. Such as throttle--some control speed of a motor, some control torque, and the feel and usage is different.
***but you can do a search for the names and part numbers on the labelling of the controlelr and the display, just in case. (we can't do this for you because none of that info has been provided) You might get lucky and find the same setup has been used on another similar scooter out there that's still available.
