Rediscovery

I went through my Amazon order history of e-books and noticed one of those books was not on my Kindle app. Going to the website, while being logged into the website, it didn't recognise it as a purchase. I sent an email with the order number and date and explained I somehow seemed to have lost access. Within 20 minutes a response. They found it, to which device would I like to download it again? Answer to that email. Within 2 minutes it was back. Great customer service!