Errr.... I think you may have misunderstood the requirements to claim. There is "Proof of Postage" and "Proof of Receipt"
To claim for, I presume, a failed "International Signed For�" you just need to produce the barcoded slip you received when you posted the item. This is "
Proof of Postage". (You can also produce the
receipt the post office gave you when you actually paid for the
postage.)
If, (for example in an E-bay transaction), the recipient claims that they never received the item, and won't pay you - you can ask for a copy of the signature obtained when the item was delivered and signed-for. This is "
Proof of Receipt"
To
claim for an "International Signed For�", you only have to provide
Proof of Postage - It does not mean you have to produce a 'receipt' for the purchase of the
item you posted. They will, of course, have to make their own checks to confirm that the package was not delivered.