took wrong replacement and said we dnt have it

I had purchased a bulb from snapdeal.com on 26 june 2014 at order id. no. 2326454576. It was damaged and i made a replacement. The couriour person took the wrong replacement and he ook my 1tb western digital hard disk. I called him and he said ” i have sent your shipment to the company” . 1.From 1 july im calling snapdeal.com 09212692126 and everytime they said to me that we are escalating your call to the concern department and you will get a call from us. 2. from last 10 days they said that we got your harddisk and we will send it ASAP. 3. today i called them and they said we have no confirmation of your hardisk and we are not responsible for it. NOW THE THING IS THAT I HAVE THE REPLACEMENT PRODUCT THAT I THEY HVNT TOOK AND THEY HAVE MY HARD DISK WORTH RS 5000 AND MY DATA WHICH HAS NO COST TO COUNT . THIS COMPANY IS TOO IRRRESPONSIBLE AND THEY HAVE TAKEN MY HARD DISK AND NOW THEY ARE SAYING THAT WE HAVE NO CONFIRATION.IT MEANS FROM 25 DAYS THEY WERE MAKING ME FOOL . THEY ARE LIARS AND THINK THAT CUSTOMERS ARE IDIOTS. AM I A SLAVE TO THEM THAT I AM CALLING THEM DAILY AND THEY COULDNT CONFIRM MY HARDISK RECIEVED TO THEM OR NOT . IM SURE THEY HAVE RECIEVED AND THEY HAVE LOST IT NOW THEY ARE MAKING REASONS TO HIDE IT. KINDLY HELP ME OUT OF THIS ITS BEEN A MONTH THEY ARE NOT SOLVING MY PROBLEM .