It's scam. I recieved this letter too, but after i recieved next letter from dmitriy@exrates.intercom-mail.com:
"Hi there,
Attention! Important information!
Exrates exchange does collect any investment charges at the moment.
Please ignore emails with the "Your investment opportunity - JUST TODAY!" subject and do not respond to such provocative emails from non-official accounts!
We would like to remind you that Exrates never requests transfer of personal funds to any accounts.
We remind you that there is a system of privacy policy that you will find by the link below:
https://exrates.me/privacyPolicyBest regards,
Exrates.me team"