if booked with a UK or US credit card raise a dispute and do a chargeback. Make sure you have the cancellation email and other evidence, You can do this even if SAS is supposedly refunding you, Its far simpler - as the onus is then on SAS to push back against the disputed amount, which given their present incompetence won't happen. but also they have no basis to push back.
As this is now going on for 7 months, the covid excuse is running a bit thin: Airlines has started and failed in shorter time frames. I'm getting worried there's now such ill-will that SAS will go bust in the recovery as their previous regular flyers avoid booking them.