I think , currently there is no any HDFC offer (Festive Treats) available. Reliance HDFC offer is only upto 2500/3000 only. This too already expired I think, but you have to re confirm again at reliance (Be noted that cash back should be mentioned on the charge slip, otherwise we are not eligible).
We can not expect Diwali time offer (huge discount, cash back upto 9000, 3 years warranty, sound bar,.....) on 26th. Every year it is only during Diwali, then they expand 10/15 days, that's all. We can expect the same only on next Diwali.