If any of the user getting frustrate with unknown messages and mails in Gmail then Gmail offers you a best feature called mark as s spam. Once you mark someone as a spam then damn sure you will never getting the messages from those unknown users. But do you have any idea, how you can mark someone as a spam? If no, then find the complete details here.
Mark Gmail Message as a Spam:
• First choose the most supported browser for your Gmail account and go to sign in page of Gmail.
• Once you reached over here, then enter your email address and password and hit the sign in button.
• Once you entered in your Gmail account, select the mail which you want to mark as a spam.
• After selecting click report spam.
Once you mark it as a spam, make sure in future you will never get the message from them.
Sometime it happens with most of the users, they by mistakenly marked as a spam. So, follow here to mark as a not spam.
• Same as above, go to your Gmail account
• Then click on more option
• Now open the email
• Here you found the option of not spam. Just click on that.