Spammers intend you to follow up using a link or perhaps other contact details within the email not reply to the email.

Spammers will use fake email addresses, hijack insecure SMTP servers etc. for the sending of spam. They are better at this game than you will be at tying to trace them by a long way.

Why can't I get it through to you Les? The only people you are likely to affect with "revenge" methods such as returing to sender are innocent parties.