I`m assuming they`ve opened it in paypal, because their out of time on Ebay to do it.
if you can`t prove delivery via a tracking number, then they will win i`m afraid, so you may as well deal with it now, rather than later 🙂
Postage receipts/tracking details should be kept for at least a year, because that`s how long customers can do chargebacks. Anything i ever sold/sell, i would print off the paypal payment and then staple the receipt to it and put them aside. Always a good idea to add tracking to the sale as well when you mark as dispatched, this stops this happening in the first place.
