Air India Express — Not yet received full refund

I had booked ticket from COK to DXB for 14th July 2020. As my daughter, Shreya( who was a passenger in it) got covid infected, we had to cancel the flight on 13th July. Though cancellation was done by the travel agent 24 hours prior to departure, we didnt get full refund. The excuse was given was it was vande Bharath flight. Kindly make initiatives for full refund.