Just as an indication where I stand with my cancelled flights SIN - CMB - SIN for travel dates 30/04 - 04/05:

06/04 Flights were cancelled and I called the same day and asked for refund. They confirmed over hotline but I never received an e-mail confirmation.

07/04 Completed the online form and asked for refund again. Just to have it in writing as well.

09/04 SQ sent an email and offered full refund or flight credits again and I completed the online assistance request form again.

11/04 SQ confirmed that they received my request for full refund.

04/05 Got the final refund notice from SQ with information that I'll receive refund within 4 to 6 weeks, to allow time for the banks to carry out the necessary processes for payment.

Will let you know when the money finally reaches my account.