Who sent the order information? If paid by Paypal then they are who you should be contacting.
Buying as a guest means that the Ebay Money Back Guarantee DOES not apply, and is never a good idea, as you have to use the purchase details to open a case, and there is no record in your myebay of the purchase.
Have you really deleted all records? Emails are not completely removed just because they are deleted, they should be in Trash.
