Payment hold but fees paid to Amazon

I sold and dispatched my order and already received by my client nearly 5 days now and confirmed but no payments. I know Amazon hold the money but I wanted to know where the money is setting? is it on Amazon bank account? or the buyer has not paid the money yet? And whose earning interested on the money? Please help as I am not sure

Here you can view the Payments Summary, along with your current balance:

As a new seller who registered to sell on Amazon on or after 15th August 2016, you are subject to the Estimated Delivery date reserve.

The money you make from a sale will be held in your account for at least 7 days after the estimated delivery date of each order. Then, it will be added to your available balance and disbursed at your next scheduled settlement date (usually takes 2 weeks). This is a permanent feature.

Also, Amazon will not release the funds earlier, despite they state in the Help Pages that they will consider the actual date of delivery.