Groupon India / Nearbuy — online voucher of barbeque nation

Address:

Kolkata, West Bengal, 700091

I had purchased a groupon voucher for barbeque nation (Non-veg lunch) from nearbuy.com on 6 nov 2017. Due to some reason, i could not use this voucher. Today when i went to the merchant (Barbeque nation), they said that the voucher had expired and they (Barbeque nation) requested me to contact nearbuy for voucher extension. Barbeque nation also informed me that they only receive the money on redemption.
When i contacted nearbuy, they outwardly rejected my request for extension, saying that the merchant can only do the extension. Nearbuy also said that on purchase of voucher, the money gets immediately transferred to the merchant which is in clear contrast to what the merchant (Barbeque nation) is saying.

Now i am in a fix with my voucher being not usable (853 inr). Ironically the price of the lunch buffet is cheaper, even then i cant use my voucher. Please help and advise.