Indigo not giving me refund of Cancelled filght

Hey, I'm from Nagpur. I booked two tickets from Nagpur to Pantnagar for my mom and dad's vacation. Their first flight was from Nagpur to Delhi and then Delhi to Pantnagar. The date was April 30th, and the flight was around 11 PM. We were almost ready, all bags were packed, and around 8 PM, we got a mail that the flight via Delhi to Pantnagar got canceled. We understand that it happens sometimes, so we booked an airport taxi from Delhi to Pantnagar for some 270 km, I guess! We talked at the airport about that, and they said that we'd get a refund for this flight.

But it's been a month, and we haven't even received a mail from Indigo. Yesterday, I mailed Customer.experience@goindigo.in, and they replied that we are getting a partial refund, but why are we getting a partial refund? The flight got canceled by Indigo only, so what should I do?

And yes, I talked to a Nagpur Indigo office person. They checked and told me that I am getting a refund of 2743 rupees. I was like, "WTF, this is not even half of the money, I guess."