Nykaa.com — Received Duplicate product and nykaa is not taking the product back

Order id: NYK[protected].
product : Narciso Rodriguez For Her Eau De Parfum.

I received a duplicate product
The serial number on the CAP and the bottle are different and I reached out to Nykaa multiple times but they were not ready to take the product back.
The serial number on bottle is 3 an on cap its 7(that too vary hardly visible)
Now I am stuck with duplicate product.
The order is worth 6396/-
I really don't want to keep the product that is duplicate for this amount.
Please find the images for reference