Reliance Trends — wrong information given by the staff

I shopped for almost 6500/- on 17th oct from reliance trends, ansal plaza, palam vihar and the payment was through credit card. Infact they gave me a membership card saying that i can exchange my stuff at any of the stores in india by showing that membership card if in case i don't have the bill. Since i am from assam and i need to exchange some items, i don't have the bill however i have showed them my card as per there guidance, now they are not accepting it. It's my humble request to look upon the matter and find a solution asap. Try not to fool the customers with wrong information.