what happens to post without stamp
No Return Address. If there is no return address on your letter or package, the post office will try to send it to the recipient with a Postage Due stamp. The recipient will have to pay the additional postage before being able to receive the letter.f the post office returned your letter with an Insufficient Postage stamp, you can simply cross off the stamp, add the correct postage and place it back in the mail box. The original stamp used is reusable in this case.