I am also affected by Singapore Airline's screw up. 30 days to go till departure date and yet they cannot offer me an acceptable solution. All my trains (first class no less), car rental, transport connection, hotels, are all booked and are all non-refundable. So how are they going to provide an acceptable solution???
So far, what I have received is an offer to downgrade to econ and some sucky S$150 inflight voucher and an officer for upgrade voucher. I didn't get to ask much on the phone as the customer service rep seems clueless. I asked to speak to a manager and I also write an email in with the details of my flight booking and it's been 5 days.. no one has called me yet. SERIOUSLY!?!?!

yewgene is absolutely right... devil is in the details. I read a Facebook post from several other unhappy customers that the voucher is for the SAME ROUTE valid for 12 months and no one has come out to clarify on what class can the voucher be used ... so which normal person pays full fare econ tickets for a family vacation for the SAME ROUTE within 12 months? Chances are that you get a worthless piece of paper as a con job to appease us now.

Also, no word on REFUNDING THE DIFFERENCE? e.g. if the cheapest econ ticket is only S$1K on their website vs. full fare of $1.5K ... will the pay the differential calculated from S$1K or $1.6K? No answer from Singapore airlines on this.

That type of crap "WORLDCLASS" airline is this? Their service is getting from bad to worse. We should all fly the Emirates and Qatar airways since that's where SQ's best people are being poached to go .. now we know why. SQ is no longer reliable ... beware people, you may get screwed even though you have booked a ticket with them.