If I'm understanding you correctly, you had the package sent to a forwarding or holding service based in the United States, but that service ceased on October 7th, a few days after you committed to purchase an item from the United Kingdom.
Your eBay claim was likely refused because the eBay Money Back Guarantee does not cover items sent to forwarding services or similar. Your best course of action would have been to request that the seller cancel the transaction and provide eBay with the reason "problem with address" which would have ensured that she would not receive a "ding" to her account for the cancellation. You could also reassure her that you would repurchase the item with your new address once the item was relisted. It does sound as though she may not have been all that cooperative had you done that, however.
I think at this point you might as well leave the PayPal claim open and see how it shakes out. I don't remember if PayPal has a policy associated with redirected/forwarded items the way eBay does, but I don't think that you would have got any further with the eBay claim had the appeal been allowed to continue. As you may have guessed, I don't think you'll be able to reopen it anyway.
How does the seller know that the package won't be returned to her? Did she indicate on the customs form/address label that the package be abandoned if it proves to be undeliverable?
