You are in a tough spot, but until you have money in hand, you don't have to do anything. If the transaction evaporates, you might let the "final transaction fee" go as tuition for a lesson learned.
My small handful of ebay disputes have always ended in frustration. As a seller, protect yourself. As has been said before, photograph all the serial numbers, and make sure that delivery was confirmed. A required signature is worth a few dollars and a few days wait for a costlier item, although it is a major nuisance for the buyer.
Allow other payment and delivery options, for a whole system I presume that you were charging AT LEAST $50 shipping, it might be worth a drive to the next state for a cash transaction in person.
Ebay/Paypal jerks you around whenever you start or change an account. There MIGHT be a legitimate reason for the address-shuffle, but it is a huge red flag.