Another data point.

Called 2 nights ago to cancel award booking and rebook new flight. Called approximately 5pm PST 30min wait but got a competent and helpful agent who cancelled the original booking and created a multi-class booking for the second flight, and put a hold on it until the miles were credited back into the account. 48 hours later miles were credited back.

Called again today around 5pm PST, 20 minutes hold and was able to get another agent to confirm the ticket, and fully book another multi-class award without issue. Surprisingly best service I've had with SQ in years back to back.