I had two of these scammers going at once...

I would take the email from the first guy, and paste the payment into the reply to the second guy and claim that the money was sent. Naturally he'd freak out and want it fixed immediately. It was a good laugh. I had both of them calling me 3x a day trying to get me to correct the mistake so they could pick the cash up at western union.

Everytime they called I'd say "Who? Who? No wrong number". The confusion and frustration in their voices was worth it.

Just looked and I must have 100 emails over 3 month period.

Finally they asked me "What are we to do now that you send my money to the wrong person?"

To which I responded

"Could you send me another fake cashiers check so we can start over? It's been so much fun wasting your time for the past 3 months! I can't wait to do it again!"

Naturally he didn't respond and I haven't heard from him since.

The interesting part was that the 2nd guy also disappeared...so I suspect they were working together or knew each other.