Yes, you can use the ON/OFF button on your air conditioner’s body unit to turn it on and off. However, you won’t be able to change the temperature setting.
If the air conditioner was set to cooling when it was last used, it will automatically turn on set to 24 °C. If it was set to heating, the temperature will be set at 30 °C. You can get in touch with an authorized service agent in order to replace your remote control.