Used product received from Ebay and they are not taking it back

I had purchased one bluetooth hands free from ebay (Pay id no:35636932386 for Rs.5800 item ID 181312645247) Where it is mentioned in their website that it is brand new and used one but when i received the product i found that. 1. The seal is not proper and broken 2. There was nowhere mentioned in the product specification about the warranty due to which anyone can assume that it will be there . I came to know only when I got the product and in the mid of the way where I had received the product. 3. There was date written on the the product by red marker 15/01/2014 which means it had already opened before sending to me. And there are lots of chances of being used, 4 Clip seams not so new as it is always loose while clipping which is due to only when it is used before. 5 There was no any seal on the display as confirmed by seller. They asked me to provide the snapshots when I had provided them now on 10/02/2014 they contacted me and saying that it seems not used one. Where my question is that why it has been opend before and if there is someting written on it it means that it has been used by someone even for some seconds but it is as used one for me instead of brand new.
When I requested them they are saying they will not take it back and will not refund back my money.