Just received an email from Smartly that they are ceasing operations in Singapore and advice to withdraw all the money out before 27th April 2020. Should I wait or withdraw now?

No one will know what will happen within the next 1 month. For other robo investing platform, they could continue to employ DCA method to buy when the market is low (currently). But due to the closure of smartly, I am afraid that you can't explore that option.

Hence, it is your decision to make whether to cut lost now, or withdraw in 1 month time (hoping that the value will increase).