Amazon India — worst delivery by amazon

I purchased an amazon basics product on 30th of april 2018. The eta for delivery was 4th to 6th may i. E 4 days to deliver one iphone charging cable. Today is 9th of may and i still have not received my product. I have made complaints on facebook page, they told me to fill a form or chat with the executive, but whats the point, all they say we are trying to get it done and i still don't have the product. My charging cable broke and i ordered from amazon just to get the best delivery, because flipkart and snapdeal usually take more time. But seriously this is the worst experience ever. I never expected this from amazon.

P. S : i am an amazon prime member.