Here is an idea on how to make sure the receiver doesn't deny receiving the item.
1. Add a barcode to the packaged item
2. The receiver has to scan the barcode using your mobile app before the traveler hands over the package. Your app will then display a passcode that the traver recognizes.
This ensures that you are certain that the receiver is who they claim to be and also that they received the item.
This ensures that you are certain that the receiver is who they claim to be and also that they received the item.