Filpcart — Received the used phone instead of new phone

I had order new phone in flipcart and received phone on June 23. During the package receiving the original seal was open and sealed with some other sticker. After receiving the phone I checked it there no any external damage so received it. After some time I came to know that some had used the phone. I found a message in the inbox dated a week before receiving the phone form amazon and vodophone. So i raised the complaint in the same date of receiving the phone. After using the phone I came to know that the phone battery is getting drained quickly. So I raised the complaint for that also. But almost After speaking with customer care serval time no response from them. I think it's a refurbished phone I received. Pls guide me.