Flipkart — Expiry of gift cards and forfeiture of the balance amount

Address:

390007

I have received four gift cards from M/s Flipkart which was as a result of redemption of loyalty points from my credit card. The amount was for Rs. 5000 each (total Rs. 20000). I have used @ 10000 of this and the balance remained unused and the validity expired.
Now the company is refusing to extend the validity.
I seek your help to get this extended as this policy is not at all customer friendly as the customer loses this money and it straightway adds to the profit of the company. What is the logic behind this?
The company can charge a penalty for this mistake by the customer but forfeiting the complete amount of Rs. 10000 is not correct.
I have attached details of the mails which I have exchanged with them.