Flipcart — Purchase of moto x play (with turbocharger) under exchange offer

Address:	Indore, Madhya Pradesh, 452010
Website:	flipcart

I am a resident of indore and under pin 452010 covered by ekart office at metro tower, near mangal city mall, vijaynagar indore.
I had placed an order on 23.07.2016 for purchase of a moto x play mobile as described above under exchange offer of my old moto g mobile bearing imei number [protected] (Purchased on 11.07.14 through flipkart vide order id: od[protected]). The payment of the new mobile was already made by me on 23.07.2016.
Today the representative of ekart came to deliver the new mobile and first checked the product to be exchanged. He was satisfied with the genuineness of the mobile to be exchanged. However, he rang up his boss i. E. Team leader one mr. Mukesh, at the office to confirm the exchange product for which he sent some photographs of the mobile for verification. After a while the boss contacted the wish master and clearly instructed him not to give delivery of the new mobile as the old mobile for exchange did not match up to the company's requirements. He said that the exchange was only of mobiles with 16 gb memory whereas the mobile for exchange is only of 8 gb memory.
Let me be clear that there was no such condition in the application for purchase of the product under exchange offer that the mobile to be exchanged should be of 16 gb memory.
After prolonged discussion with the team leader, it was agreed that the mobile for exchange would be taken to the office for verification and the new mobile would be in my custody until a decision is arrived at.
Since the local representative of ekart has come up with a new condition that did not exist in the application form submitted by me, why should i accept the same and moresoever since the company accepted my application after verification of the details of my old mobile and has not asked me the internal memory capacity.
This is for your kind information since the matter has not been resolved.