GoAir — no refund for cancelled flight

I have booked flight for 2nd june from nagpur to pune in feb 2020. And i have tried to contact goair for cancellation but was unable to do so. And i had to reschedule my flight to 26th jan 2021 as i didn't had any other options as no cancel tab was available then on goair website. Now i am trying to cancel the flight and refund amount shows rs -1978 (Negative). When the flight was cancelled why i am not eligible for refund this seems to be unfair, i want to cancel and get the refund.
(Pnr j6kbsp)
Service request no. G[protected], g[protected], g[protected] no response on email and phone.