Spice Jet Airlines — Covid-19 shell credit issue

Hi,

This is regarding my booking from Kolkata to Delhi on 27th May which I booked before lockdown.
Due to Govt & Airline guidelines then, all the travels till 31st May was cancelled so they announced for the credit shell rather then providing refund which the same passengers can use till 31st March 2021.
Now in the month of Dec 2020 I tried to book tickets from that credit shell but I found there is no money so unable to book any tickets.
After making multiple long efforts I somehow reached to customer care and they said they have given the refund of the amount to the agency from where I have booked the ticket.
Fortunately I myself control that agent login of that portal so I found no refund, no credit as such since Jan 2020.
Now no credit, no refund and they are also unable to provide the proof of the refund process or any transaction number.

No information given in my account section of SpiceJet regarding it.

Please help me to file this genuine complaint against Spicejet.