Hi!
My name is Tomasz Kustra, and I am from Poland.
What you require is available, but not simple.
Quite simply emails of top 10K reviewers could be obtained.
I can do it for 100$, but only around 2-3k of those reviewers will have emails.
To get more emails much more sophisticated approach is required.
I have done such thing some time ago, gathering as a result around 200k emails from Amazon US.
Here is a part of it:
https://www.freelancer.com/projects/postgresql/Fix-Data-Scrapping-Perl-Script/
However it would be much more expensive and would take much more time.
Let me know if you are interested
Regards
Tomasz