Return window not opened

I’ve purchased a laptop from amazon.in. Got this laptop delivered on 16th july. When I start using that laptop I felt that the laptop is very slow, its a i7 8th gen laptop but performing slower like an i3 laptop.So i went to amazon.in sites and navigate to orders. But what i found was delivery status was preparing to be dispatched. I thougt to wait for some time. Did same next day and found same message. Upto 26th july it was showing preparing to be despetched and on 27th july it was showing delivered on 16th july and return window was closed on 26th july. return window never opened and was showing like return window closed. I contected amazon customer service on 8th august, and they gave me information that return window was closed on 6th august. Once again contradictoary statement. Amazon app showing window was closed on 26th july, amazon service center says 6th august, and in reality return window never opened. I gave proff to my statement but amazon customer service says they cant help me.
Here return window is not opened, amazon system is faaulty and still they are not helping me. Amazon costumer service is wroast in world