Unknown person writes comments and I can't write back to the email

Hey
I have a person who writes me really negativ emails about my travel, how I’m supposed to write like that and I shouldn’t even travel whit such commentaries etc.

I’d like to write back to this person but I can’t, it comes a failure email back.

The email-adress and the computer is:
[Details removed]

I have this email now under Spam but it’s actually not the first email he wrote and I don’t want that he can see my homepage anymore or even write me with this email. Is this possible to block him?

My homepage is: http://www.tanileha.com
Greetings, Nathalie