Amazon India - Wrong product delivered

I ordered one plus * from Amazon on October *. I am a prime customer and the product was expected to be delivered on **th. They didn't deliver the product on time. On **th also, they didn't deliver the product. On **th they delivered the package. When I opened the package, I got a phone worth rupees ***-***. I complained about this to Amazon and they asked for pictures. I sent them the pictures and they are now saying they will do an investigation and get back to me and this can take *-* days. I wonder if they are the ones who have failed at every count, why should I trust them? I have been cheated. I guess they bought time by not delivering the product on time to tamper the package.