Possible problem: You have been pressing power button on the device for too long time (over 5 seconds) and your RC was unlinked from Scooter S.

Recovery steps:
Step 1:Turn off your device, short press power button on the device.
Step 2: Turn on your device, short press power button on the device (Display backlight will turn on and off for 1 second).
Step 3: Simultaneously press two central buttons on the remote control (B and C) and hold for 3 seconds.
Step 4: Turn off your device, short press power button on the device.
Step 5: Turn on your device, short press power button on the device.
Step 6: Press the unlock button on the remote control. Smart Scooter S is ready to use.