Reliance Trends — Bough enough for the offer they've mentioned in store but not was not given since we bought it in two different bills

I first went to my nearest trends store bought a couple of dresses since the collection wasn't much where my bill amount was 1698 rupees. Planned to go to another trends outlet which is bigger thinking it'll have better collections. Found a couple and bought it and the bill amount was 1797. According to the offer they have right now if we have purchased for more that 3000 we are eligible to get a pressing cooker at a cost of two hundred. I had a combined bill amount of 3495 rupees but was denied because it was on two separate bills. I find it to be outrageous as i did shop for more that 3000 rupees on the same day and using the same phone number and was not given the offer. Needing it to be on the same bill is outrageous.