Vishal Mega Mart — offer shown but not given salesman not concerned at all

Hello sir, i am ajay kumar gupta, today i went to vishal megha mart m. P nagar bhopal. I selected 4 t shirts under the offer buy 3 get 1free but when i went for billing the offer was not visible there and they were asking money for all the 4 t shirt, when i told them about the offer no proper response was given.. So my concern is that if the offer is over pppp why there were offer tags.. Who is responsible for the time i wasted in selecting those t shirts..? I wouldn't have minded much if i would have got good response from salesmen. I am a regular customer of vishal megha mart but this behavior of mart was really new so ultimately i have to leave those t shirts not because offer was not given, but because no one was concerned with my problem. Although i left my complaint on the suggestion register but i really want someone to pay attention to the problem...