Update:
So finally today I came to know about the actual case.
This is the chronology
Day 0 (15th April 2024): I tried to book Mumbai to Frankfurt ticket on Balmer Lawrie app. The transaction failed once and once it did not show anything. I checked in the transaction history it did not show any ticket. After that I booked Multi city ticket (BOM-FRA and Paris to BOM) on MMT. The ticket was generated instantly.
Day 1: I got the refund for the failed transaction from balmer Lawrie.
Approx 24 days passed and I took the flight from BOM to FRA and enjoyed the my tour.
Day 41: I reached CDG airport for my return flight. There I was denied boarding pass stating that the ticket is locked by the airline. After a lot of hassle one of the Vistara guy helped me to unlock the ticket and I reached back Mumbai. Apparantly they told me that the ticket from BOM to FRA was a no show and hence the return ticket was blocked.
Many days passed and I did not received the refund from balmer Lawrie nor their app showed anything. It showed only one booking ID. I talked to customer care and they told me that there was only one booking for which refund has already been initiated and they can't find the second transaction ID.
After a lot of mail exchange balmer Lawrie agreed to refund and they again sent me the refund details which they processed on Day 1. I sent them my credit card statement and told them that there were two transactions and I have already received the refund for one of the transaction however I haven't received the transaction for the second transaction. To my surprise today they have sent me the confirmed ticket for BOM to FRA. I seriously did not expect this. I immediately replied them that both the transactions have failed and afterwards I had booked a multicity flight ticket on MMT.
I also attached the ticket and mail from MMT.
Meanwhile the no show ticket problem struck in my mind and I checked the ticket details for my CV points. To my surprise the ticket details of the CV points i.e. the actual journey taken from BOM to FRA matches the ticket details of balmer Lawrie.
I kept thinking how was that possible as at the time of check-in I had showed my MMT ticket as I did not have any ticket details from balmer Lawrie.
Now technically I have travelled on ticket issued by balmer Lawrie and the MMT was no show hence both of them will deny the refund for ticket.
IMO this is a mistake on Vistara side as they shouldn't have allowed 2 different ticket bookings for a single passport number.
This happened because while checking in they swiped my passport on the machine to check the Visa details in which both of the (Balmer Lawrie and MMT) PNR showed up and the attendant selected the balmer Lawrie PNR.
Now in this scenario, accordong to you, who should refund the amount? What is my best bet the get the refund?