Reebok India — Not providing bill and not giving stated discount

Address:

West Delhi, Delhi

Today, 21 November 2012 I went to a reebok outlet in rajouri market branch in delhi. Reebok has a flat 50% off for quiet few days. First the owners didn't give 50% off ie. I was given only 30% off and as i asked for a bill that was also not given. The 20% off that I did not get would have most probably gone in the retail owner's pocket
Hope u would take some serious action
I've attached a photo of the outlet
On the entrance you can see that flat is covered with a paper and only sale 50% can be seen