Paypal Inc demanding payment from Ebay seller for an item that was delivered, refusing appeals for dispute San Jose, California

Pay Pal has placed my account into collections for $580 unfairly because of an Ebay sale where my buyer reported the item as not sent.  I checked with USPS, the carrier, who informed me that the buyer had provided an undeliverable address, and that the item would be forwarded to another address listed under his name and arrive in two weeks.  In the meantime, Paypal contacted me, insisting I pay them $580 for a failure to send the item, which I appealed, since it seemed obvious that the item simply had not arrived yet due to the buyer's undeliverable address. 

I have since not heard anything from either the buyer or Paypal, and noted that on February 2nd the item arrived at the address.  February 22nd I received a letter from a collections agency pursuing the $580 that Paypal believes I owe them, even though the item is listed as having arrived.  I have since emailed the buyer, requesting that he inform Paypal of the item's arrival.  Reports against Paypal have been filed with the Better Business Bureau and FTC Consumer Protection Agency.  Additionally an FBI Internet Crimes Complaint has been filed against the buyer for internet fraud.