Eithad Airways - Refund not Received for cancelled ticket

I had * tickets booked for a travel planned in the month of March.
However owing to the Covid Situation , it had to be cancelled.
The cancellation request was placed on March **th with Etihad Airways and I recd. the confirmation for the same.
I was informed that the refund would be recd. in my source account after ** working days.
However it has been over ** working days now but I have not recd. any of the refund money as yet.
The airlines claim they have done the refund but are not able to provide any details to me for the same.
They are expecting me to check with my bank without any details being provided by them.
This has been going on for * months now,when everytime I reach out to them , they say they are checking with some internal team. I think they have strangely captured wrong details of my bank/ card on the ticket.
But no specifics are provided for the transaction, that they claim to have refunded.

It is an extremely distressing situation, as you would appreciate,given the pandemic catastrophe that we are all dealing with.

I am left with no recourse, but to report this as a fraud with yourself. I understand it may be just one transaction in the larger scheme of things, but for me as an individual it is a lot of money that is even more critical in this pandemic time.

I am writing to you with great hope and expectation that I would receive a favourable response on the same.