Amazon India — asus zenfone 2 laser 3000 mah li-ion 100% original battery for asus zenfone 2 laser ze550kl zd551kl (c11p1501) - black regarding refund and return

I made a purchase on 24th october.

Order number - #[protected]

Name of the product-asus zenfone 2 laser 3000 mah li-ion 100% original battery for asus zenfone 2 laser ze550kl zd551kl (C11p1501) - black

Sold by-: sai baba electronics

After receiving the product it was found that product is defective. So, i requested for refund on 4th november. They asked me to self-ship the product. I did everything they asked me to do. Now they are saying you talk to the seller regarding the refund.
I talked to 5-6 customer care they all said that money will be refunded but now its more than a month but my money is not refunded. They asked me to track the order status. All was in vain. To be very frank i don't know now whom to contact. I am tired calling customer care agent. My argument is that if you keep such seller then you must have the courage to talk to them and help in customer refunds. But i don't know why they are more helpless than me.