Hi, I once had a buyer pay by Paypal but a friend did it for them with a different account name, at the time I was selling a large amount weekly and the alternative name appeared as a totally unrelated (to any eBay item id) entry in the my PayPal account.
When I e-mailed a reply in response to the PayPal notification I did not get a quick reply back until the 'payer' had contacted the winner, if only they had told me first it would have been a bit less messy.
Could this of happened in your case ?