Tatacliq.com - Tatacliq sent used mobile

I ordered MI **X mobile phone from Tatacliq.com on **st October **** and got the package on **th October ****. Mobile box has scratches and stains. I had contacted Tatacliq customer care and they've asked me to open the box. Accessories inside the box too have scratches. I had sent them all photographs before and after opening the box. We can clearly see that it's a used product but Tatacliq is not accepting the return request. They were asking me to provide a Pre-activation certificate from MI India. So I went to an Authorized MI service center and they confirmed that the product was activated on *th October ****. ** days before I placed the order. Service center gave a printout of pre-activation details. I shared that too with Tatacliq now they are saying it doesn't have sign and seal and declined the return request.