Fiido D3 Electric bike 3 speed modes pedal assist

Fiido D3 Electric bike 3 speed modes pedal assist on screen won't turn on it was working fine all to day to just can't understand why is not switching back on still taking the charge perfect In good condition it aswell Key Features: Range, Adjustable Height, Foldable Voltage: 36V Foldable: Yes Wattage: 200-250w Wheel Size: 14" Max Speed: 10-25km p/h electric only Range per Power: 25 - 40km Maximum load: 120KG Maximum grade: 20 degrees Motor power: 250w Colour:White Horn and Led light on the front Includes charger Dublin15 blanchardstown 0833972833 and my WhatsApp number 0833972833