If your delivery fails because of poor service from the postal system, contact Customer Service immediately after you have attempted delivery. Tell them that the parcel had no postmark and no one was available at the address to accept delivery. They will be able to give you further advice on what next step to take. If there is a problem with the delivery because the recipient refused the package, then this story will vary depending on the reason given by the recipient. But in either case, you will not know why the delivery failed to arrive at its destination. You must investigate whether there is something wrong with the delivery system or not. If you cannot contact your recipient, please try again later.