Just respond and let them know they can come and pick it up now, as you are a trusting bloke. Organise a time and give the an address a few doors up. At least you may waste their time and money
With most of these scams they do a dodgy over payment to you and show you account figures from a dodgy website. They then demand and threaten you to repay them the $5000 extra they allegedly put in your account.
The last one of these I had I led down the garden path with emails etc, got the details organised payment and pick up and then my last email to them I included the full email conversation and CC'ed it to Crime Stoppers, funny their phone was disconnected 5 minutes after that and they never replied to another email?
Jas