I can't help with your exact Aeroflot issue. But, I would recommend that if you don't get the refund VERY soon, you file a dispute with your credit card company. You need to file within 60 days of your purchase, so your time is quickly running out. Your credit card company may end up being the only way to get your $1,300 back. You'll need to show them the T&Cs that state 24 hours cancellation policy, proof that you cancelled in that time period, and let them investigate. If you are able to provide them both those items, you should be ok. If you wait past 60 days, you'll have no method of recourse left (other than small claims or similar)

Good luck.