[help] Email returned spam question

I put together a crappy site for my dad's business...let's call it "example.com" for examples sake.

On the site my dad's email is listed. It's completely different from example.com.

Somehow I'm getting a ton of junk emails like this with my dad's website in the address, for example:

[email protected] and Delivery status notification (failure)

It seems junk mail is being sent to addresses like:

[email protected], [email protected], [email protected]

and is getting kicked back.

Why would these names have my dad's "example.com" on them and why are they coming to me?

I get hundreds of these on some days and it's causing me to reach my email storage limits.