Anything with a battery inside and power banks is not allowed in checked bags and was probably intercepted in transit in India. BCAS makes the rules which CISF implemented. If they removed the drone and power bank it's has been documented. Indigo will take no responsibility for things done by the authorities. Hence good luck with shaming them.
I had a similar case with a friend's son who was on 9W from BKK to AMS via BOM. Bag missed the connection and was delivered days later after being opened with brute force. 9W basically said this happened due to CISF action which they can't be held responsible for.