All e-mail addresses used in this scam have been reported to Yahoo and they've 'taken appropriate action'. Not sure what action as they won't disclose, but hopefully they've shut down the accounts. No doubt the scam will spring up again under another pseudonym but at least this will stop them temporarily

If anyone ever gets mailed by a scammer, the e-mail providers welcome notification of the account abuse so they can shut the scam accounts. It won't stop the scammers opening new accounts, but it will slow them down.