Kalyan Jewellers — Gold card rejected as it is expired, but in fact they didn't intimate me legally anywhere

Address: East Godavari, Andhra Pradesh, 502032

Website: kalyanjewellers.net

I have purchased around 1 lakh 20 thousand rupees and i was issued a gold card which can be used as a discount/cashback for the next purchase.
In gold card the amount is 1200rs. And when i wanted to purchase the gold with this card in kukatpally hyderabad branch, they rejected it to accept this gold card, as they claimed that, points/cash expired just 1 month back.

I asked them, did you inform me that this points/discount 1% would be expired after few months/days???
Is it written on gold card issued to me??? (No where i can see that clause)
Did you written/stated somewhere on the bill??? (No where they have stated)
Did you informed me via mobile number that your points/cash going to be expired within so and so months/days??? (Didnt receive any message)

Then why are you not accepting my gold card points???

Literally they are cheating the people/customers...
Kindly do the needful asap.