Flipkart — They cancelled my order without asking me anything

Website:

Flipkart.com

I purchased a laptop on 30th July. The estimated delivery date was on 4th August, then it got rescheduled on 10th August. So, on 11th August i gave them a call and they asked me to wait till 18th August. Then i said okay but tell the delivery team to try and deliver it before 14th if possible. But then suddenly when i checked my orders then i saw my order got cancelled. When I called them they said the seller cancelled it and you will get your refund within 19th August. I said who the hell wants refund, i waited 2 weeks for my laptop and you people cancelled it without any notice? Atleast you people could have asked me if i want to cancel or not. It's not some chocolate which they will cancel whenever needed, i need it for my work. When i asked them to uncancel it they said it's against their policy. Is this how an e-commerce works?
I want to take appropriate action against them if possible