AO Smith — New gyeser making noise but service/warranty denied

I bought a new gyeser from Amazon, order Id[protected] on 13th October 2023. It was delivered on 21st October 2023. There wasn't any instructions on the listing regarding installation so I got it installed locally. It worked fine on the first day but started making loud noises from the second and with each passing day the noise is becoming stronger.
Today on 02/11/2023 I called AO smith customer care. First of all it was quite a hassle to connect but somehow I got to talk to their representative. When I told them about the issue with the new gyeser they said we do not provide service at your pincode so you can't claim your warranty.
They didn't mention any of this either in their listing on Amazon or their user manual or warranty card that they do not provide service on selective pincodes.
They sold a defective product to me and if any unfortunate incident happens who will take responsibility? I can't even claim my warranty. I spend rs. 7, 103 on this geyser. Please help.