Indian Railways — Regarding refund on train booking

Dear sir,
I booked train tickets from Mumbai to Nagpur and back for 17th April and 18th April respectively. Lockdown was announced on 22nd March so I came back home from Mumbai. As the initial lockdown was only for 21 days, I didn't bother bringing back my ticket. But as it came out lockdown was increased. As I booked ticket in offline mode, here in my hometown they demanded for the hardcopy of the ticket. They even assured us of full refund. Now on 31st October I was able to retrieve my ticket from Mumbai. Today when I went in the railway office they told me, that the refund period was for six months only and now you are not eligible for the refund. We couldn't afford losing the refund as both tickets costs about 2700 rupee. And will be a big blow to our pockets. Please look into the matter.
Thank you