Is there no way to bounce them back to where they came from?
Nope! I mean you can, but most cases are that the email address of the sender is spoofed. Even if you look at the header info of the email you'll find that the address it actually came from is different from the address they show in the reply (from) field. Even the from address differs from the domain where it originated from.....
It's an evil that cannot be cleansed.... There was a local company that had an oc<something> piped into their building, had a full room of server racks, and all they did was send out emails for companies (all day, all night). They offered me a job, and even though it is dishonest and that 10% of the emails they sent out were probably valid, I had the urge to blow the building sky high and do the world a service...... I tend to ignore those urges though...