FLIPKART - Cancellation and refund not done by Flipkart

I ordered water purifier from flipkart on **th June **** and paid ***** rupees online. The date of Delivery was *nd july **** but Flipkart failed to deliver this product and flipkart revised date of delivery to *th July**** so I waited but product is not delivered on or before *th July so I requested them to cancel the product and refund my money as I am not getting product on time and my mother was suffering due to kidney stone. I told flipkart **-** times to cancel the order and start my refund process but flipkart is not doing so everytime they say we have taken your cancellation request, you will get message or mail of refund process in next ** hrs but same is not happening since *th July ****. It's totally frustrating and mental harasment.