Amazon India — received fake supplements

I ordered a product name muscleblaze whey performance protection 4kg from amazon 19, Feb, 2019 worth Rs 5964 . The product is delivered in nearby store. Then I took the product from the store.
But when I opened the product I found that seal is opened and the powder is also spilled in the bucket.
Then I contact amazon customer service, they told me that they can't take any action because the store manager can't mark this product as picked up and tell that I have to wait .
After 2 days thei got the notification that my order is picked up. Then I again call customer care, they ask me for snapshot of damaged product and wait till 3 days so that there consent team will investigate.
After 3 days I again called amazon customer care regarding any update. Then they say that I can't get any replacement or return . When I ask the reason then the say that the resolution is coming from investigation department and they can't do anything. And they can't help me regarding this order.
According to reports 60-70% of supplement in india are fake.
Then why I consume this product. I want my money back.
If amazon can't give my money then they should send me a written letter which stats that this supplement is safe to consume and doesn't have any side effects. Then only I consume this product.
This is not a small amount, I can't throw away this product nor I consume it without any written proof.
Amazon investigation department should send a written letter to me regarding this product authenticity otherwise give my money back. My order no.[protected]