Tata Cliq — defective product sold where return policy suggest 7 days return now they are denying on return

Address:

4 subodh garden saranya apartment,bansdroni,kollata, Kolkata, West Bengal, 700070

I have bought mi band 3 from tata cliq the product is got delivered on 9th may2019. On product page retrun policy mentioned as"easy 7 days return".
I got the product and found it's defective. Discharging very fast. Not working as mentioned.
When i asked for return customer care says i have to to service center, they are denying on return.
This is a new product and it's within 7 days as per site return condition then why they are not taking the product back and returning my money. Instead asking me to go to service center.