Update: It now appears that Aeroflot will only be honoring people holding Transaero tickets for travel before 12/15/15. If you have a ticket on or after that date they say you should apply for a refund from Transaero or your travel agent.
Personally I’d also call the credit card used and dispute the charge if you’re scheduled to fly after that date.
You can also try calling Aeroflot to see if you can be recommodated after that date.
Transaero, Russia’s second largest airline, will apparently be filing for bankruptcy after failing to complete a deal with Aeroflot.
It is no longer selling tickets and will stop operating shortly.
The Wall Street Journal quotes Aeroflot’s CEO as saying that they will accommodate Transaero passengers with a flight or a refund if no alternate flights can be offered.
I’ll post an update when more information is available on this story and on Aeroflot flight reaccommodations.