Airtel offer in front of Cineplex

If you go to watch movie at Cineplex at Bashundhara city complex, you will see two big billboards beside ticket counter. There you will see that Airtel is giving offer a free soft drinks or popcorn for just a simple sms. Well I tried before but no sms reply came. Yesterday when I tried, within a second reply message came that I can get this free offer, I was very happy. But at the ticket counter they said, this offer is close now, so you are not getting anything.

My question is then why they didn’t remove those two boards of offer? I had spent time and sms money for nothing… doesn’t know how many other did the same mistake.