Amazon India — Took double payment. Not refunding since 2 months.

I made a payment through my card on 9th July which it showed as failed and I recieved an error. But the money was deducted from my account. However Amazon delivery boy said that they did not receive the money and you will recieve a refund to your account. Then on 10th July I made the same payment in cash on delivery mode and received my product.

I made my bank do proper investigation and it turns out Amazon recieved my payment on 9th July. They have been fooling me for 2 months and even now they are taking endless amount of time for investigation. The amount is not a small amount. Its getting out of control now.