hi, apparantly, paypal doesn't require/want proof of shipment, but rather proof of delivery. in other words, if you sent it with a tracking number, you'll be able to prove it was delivered or not. without a tracking number (small packet etc..), you're out of luck, exact same thing happened to me...
as far as no moolah in your paypal...don't worry, i think they pull it anyways, leaving paypal account in the red with a kind follow up email asking you to correct your negetive balance...
good luck..and yes, definitely file that claim with cp...that is when they first allow you to...what is it...75 days after delivery...X-(
Kat