Paypal hates when you do that. They dont like the credit card company getting involved until they had a chance to resolve it themselves.
Who cares... Certainly not paypal. Call AMEX immediately and open up in a dispute.
Also, File a claim with the FBI and give them the info. In the notes let them know that this guy did this to 50 other people and write in a dollar amount in the notes text (they use screening software). Give them any names and phone numbers you came across, basically all the info to make their job easier.
Internet Crime Complaint Center (IC3)
I got burnt on a Gen 1 Macbook Air from someone in the US. They tracked the guy down within a week and his family had to post the funds or he was going to jail. In a return email which the entire purchaser list was CC'd, he was begging for the FBI not to arrest him. He claimed he sent $30k to his contact in Hong Kong and the guy took off and didn't ship (likely story). Everyone got their money back. AMEX withheld payment to paypal so I didn't have to sit around and wait for them to get back to me.