GoAir — Cancellation & no refund

We had booked a round trip flight from Mumbai-Goa-Mumbai.
Our PNR number is FG6HUB.
Our flight (Flight No. G8-384) was cancelled from Mumbai to Goa (18th Dec' 2020) by the airlines. The flight which is scheduled for the return on 31st Jan 2020 from Goa to Mumbai has not yet been cancelled.
We have been trying to contact the Goair team since the past few days, however nobody attends to the call. The automated voice keeps saying that the attendants are busy and after holding for 52 minutes the call drops.
We wish to get a refund for the cancellation (as the cancellation was done by the airlines) but there is no way we can connect with Goair team.
Also while they have cancelled the flight from Mumbai to Goa for the 18th Dec, the flight from Goa to Mumbai is not cancelled.
As nobody is attending to the calls, we cannot cancel our flight from Goa to Mumbai. We are in a dilemma as we are not able to connect with the Goair authorities.
We hope that the GoAir team resolves our issue rather than avoiding our calls.