IRCTC Indian Railways
Refund not done after train cancellation

I had a tatkal eticket booked from Hyderabad to Chennai on 20/05 by Charminar Express (Train No.2760). eTicket booked on 18/05 for 3AC with PNR No. 1146178698, worth Rs. 1036. The train got cancelled due to cyclone Laila that evening and hence I left hyderabad by bus that night itself for official reasons. And I filed the TDR immediately the next day itself, and now after 6 months of follow-ups, irctc has rejected the refund stating it was a tatkal ticket and hence no refund, which is ridiculous... it is understood that if the passenger cancels a tatkal ticket there will be no refund under normal circumstances,

but in this case the train got cancelled due to a natural calamity and then why I am being rejected the refund for no fault of mine. Please guide me on how to get the refund...