In an e-mail sent by Paypal:

"If you used a Visa credit card or Visa debit card to make a PayPal transaction between July 19-21, 2002, your card may have received a duplicate charge from our credit card processor. Our processor has identified these transactions and corrected the problem within the last 24 hours by reversing the duplicate charge to your credit card or debit card account. [...] If you have been charged a fee by your credit card issuer or bank as a result of a duplicate charge, please fax a copy of your statement showing the duplicate PayPal charge to [number withheld]. On behalf of PayPal and our credit card processor, we extend our sincerest apologies for any inconvenience this may have caused you."

Kudos for the proactive handling and apologies, but asking me to send a fax to fix a problem you created? Why not a telex, or smoke signals while we're at it? This from Paypal, the payment-by-email company!

Make it easy for me to solve the situation, and in my case I'd rather copy & paste the statement (or scan it if I didn't do online banking, but I'm willing to bet most Paypal users also get their bank statements online), and e-mail it to you. I don't have a fax, and I don't start my microwave by striking stones together either. And don't argue about authenticity since anyone could Photoshop an original statement then print and fax a fake.