2.
Can you tell me where did you buy this ticket ? Have you bought a round trip ticket or oneway ? because I couldn't find your number ticket form HCM to Moscow in our system, I only found your ticket from Moscow to HCM city, but it's already used. Do you have your intinarary paper here ?
It could be having a mistake in ticketing office when you bought this ticket. Could you please wait a moment , I will contact my station manager ,then we solve this problem . Now, there is only way for you. You can buy a new ticket here , If you want to fly back to Moscow today. After that, you can bring your receipts with you and contact ticketing agency where you bought it. You can complaint what is wrong with it , then you can get a refund .