How to parse email database from mail support?

Question

gmail

There is a product and e-mail for support of this product. There are quite a lot of letters. How to collect a database of users who have ever written to this e-mail to send product news?

Answer 1

Watching how you work with mail.
If there is an address book, then look at what's in it. Often there are added all the addresses of those who wrote.
If there is empty - try to study the question of how to add all the recipients there.
If it works, then you can then try to upload the resulting address book.