Nykaa Fashion - Getting different Timex watch with almost same details

As product was on my wishlist from long time but product was out of stock so one day notification came that product is in stock that is only one left, so without wasting time I ordered the product and within *-* days tha product was delivered in evening of ** august. That time I was in market so I received the product there even I showed delivery boy in the market so when I arrived home I unpacked the product and while unpacking a made video because I usually do that especially in accessories. Then I immediately call to customer care and told them about the situation then they told me to send images of the product and said wait for *-* days. So I waited but no response from there side so i call them again then he denied for return and said seller has send the right product they have evidence then I said also have evidence but they told me to keep the product.
Then I request them to connect me with higher authority for the matter . Then yesterday evening (* sep) I got a call from there side and he also told me that seller has denied and tod me if you want investigation from courier partner then they will send *-* people to my house for investigation. Then I told them that I would talk to them but not in my house. If he want to talk then talk on phone or in public place even I can give you the product for investigation then he refused then he told me ki yehi procedure hai. This is very unethical means how can I allow some strangers to my house it's unsafe. I told them if he do any misbehaviour then he and nykaa will be responsible for that . I told them this type of investigation i don't think so you have to right to do.why they threatening us i don't understand