I received an email with title: "Updated Language Settings" from [email protected]:

You have successfully changed your default language for browsing, shopping and receiving communications from Amazon.de to "English".

Follow by second Email:

Thanks for visiting Amazon.de! Per your request, we have changed the e-mail address associated with your account

The e-mail address associated with your account has been changed. The old address was [email protected]. The new address is [email protected].

Checked on Twitter and Reddit, seems it happened April 2017, and people start reporting this issue once again on Sep 1, 2017.

The amazon account associated with the email is no longer able to access through amazon.com.

https://twitter.com/search?q=amazon%20account%20hacked

https://www.reddit.com/r/amazon/comments/6xom2j/amazon_account_hacked/