Air Vistara — refund of cancellation tickets in case of emergency

We had booked four tickets from kolkata to andaman on 23.01.20 and andaman to kolkata from 28.01.2020. Our one passenger miss abhipsha dash had met an accident and her right hand is broken and her doctor advised her not to travel at that time. At the same day our another passenger mr. Anklesh mishra had met an accident and his hand is sprained. So we regularly contact with air vistara and they assured us that they have policy of refund amount of the affected person in case of medical emergency but today they have mailed us that they will not refund the amount as our all medical reports are invalid.