I was in the same position, except with Star Alliance. Booked through Singapore Airlines using Krisflyer miles. I was due to fly from LA-Tokyo-Singapore-Sydney. However, due to the travel advice on Smart Traveller, we decided to cut the trip short and come back to Sydney last week.
Initially we had tried to contact Singapore Airlines to change our flights to fly back from the US to Sydney asap. After waiting hours on hold, we finally spoke with a representative, who explained that they needed to have the change approved and that someone would call us back. However, no one called back for a few days so we called them again and waited on hold for another few hours, before getting the same answer. After frustratingly waiting another day or so, we decided to just book a separate ticket via United Airlines, which had a direct flight back to Sydney.
I just got off the phone with Singapore Airlines about the status of the ticket, and the representative was very vague about it all. She explained that the system showed that a refund of the points has been approved, but when I asked whether all of the points are being refunded (since we were already half way through the round the world ticket), she said she did not know, but another representative would call or email me once it is ready. She was not able to give a timeframe for this. I don't think many airlines are clear on what ought to happen next, given these very exceptional circumstances.