Airtel — offer on nokia 6.1 plus

I have bought new nokia 6.1 plus from flipkart and there was an offer from airtel of getting ₹1800 cash back in the form of 36 coupons and 240gb data in the form of 20gb data per month on recharge of 199/249/448, i have done 199 recharge twice, but didn't get the cash back and extra data, i have contacted airtel customer care and they told me that i would only get cash back of ₹2000 as it is a festive offer on buying any 4g phone and will not get extra data, but i don't want the festive offer, i want the bundle offer which was promised to me at the time of buying the phone
I am fed up of calling airtel customer care who just says that i have got the festive offer and i am not eligible for the bundle offer which comes with my handset, although i have never claim the festive offer