Dell - Dell not honoring offer cash card on 2 lac laptop purchase

I purchased Laptop of Dell on **th Sep ***** (order ********* )
Dell advertised Independence day offer on their website for which they offered ****rs virtual cash card . I purchased laptop for * lac rs and laptop got delivered on **th October ****
However i did not receive any mail or communication regarding registration process for Cash Card through dell. I myself called and asked about the same and i was send a link to register for offer . The link , on clicking was taking to some other link which was asking for VPN login

I was unable to register for product.
When i dropped a mail again to dell , they simply told that offer is closed and last date of registration was **th October ****. If my Laptop is delivered on **th and offer is closing on **th , there should be clear communication from dell stating that i need to register.

Kindly note below facts
*>I purchased laptop on Sep ** and it was delivered on October **th ****
*>I was in constant touch with dell for late delivery of my laptop. Throughout this process, i was never communicated to register.
*> When i myself enquired whats issue, then they send me a link which on clicking was taking to some wrong URL.
*> When i was unable to register and got back to then , they said offer is closed.
*>Imagine laptop is delivered on **th October and offer is closed on**th and i have not given any email or link to register

I have been dell customer from * years and this is my *th laptop from dell and i never faced any issues wrt warranty or fault , every time dell honors it

It is duty of dell to honor any offer that they advertise in name of offer to customers to purchase product.
You simple cant post some terms and conditions in a corner of page and say see date was till **th October. It is clear case of cheating. Moreover there should be a sufficient time from laptop delivery date to redeem any offer. No company delivered products on **th october and closes offer registration on **th october, that too without any communication