Wow Momo — Coupon not accepted

Address:

Kolkata, West Bengal, 700156

I got a by one get one coupon by booking movie ticket through bookmyshow. As attached in terms & conditions, it was clearly written that I would get the free item of SAME or lesser price of the ordered item. In Spencer's, Axis mall, Kolkata I ordered a chicken cheese fried momo which costs 120/- but they told that the free item i would get was chicken steam momo which costs 85/- & even I would not get that and I would get a veg steam momo because their excuse was that chicken was finished. But at the same time when someone else ordered chicken momo they accepted the order. Then what does that mean? The chicken was available only for ordered item? And when I told about the terms & conditions that I would an free item of that SAME or lesser price, the simply refused like a street food shop. Even they don't have the courtesy of working in a branded momo shop. Their attitude was like do whatever you want.