Chargeback is the absolute right thing to do. Hope the payment processor harasses 6E a lot for you.

I don't know if it is bad intentions or simiply bad processes and poor systems. All Indian carriers have issues accepting/refunding foreign payments due to past fraud and absurd solutions to tackle that problem plus there are other central bank guidelines.

It's a small miracle you could book with a foreign card. Most foreigners have issues with that even if they are lucky enough to be ticketed. What type of card did you use?