In order to tell if an email is legitimately from Unstoppable Domains you can set an anti-phishing code on your account. All emails from Unstoppable Domains will have the anti-phishing code within the email, if an email comes through and it doesn't have the anti-phishing code it is highly likely to be a scam/spam/phishing email that you can disregard.
To set an anti-phishing code head over to your Account Settings Page and click on "Set Code".
Now enter a unique code and press "Set Code".
Once that is done, any emails from us will have that code within them.
*Please note, if you are using wallet login and you don't have an email address attached to your account this feature will not be available.