Amazon India — I am complaining about non delivery of product

I have purchased a laptop which was scheduled to be delivered on 22 nd july, but due to some personal reasons i rescheduled the delivery to a later date on 25th july, but suddenly amazon had cancelled my order with no prior intimation. Also, i had booked the laptop during the offer period with exchange offer.
This kind of experience is not acceptable from amazon who is known for its customer centric approach.
Please look into the situation as soon as possible and ensure that the product is delivered on time.