Please be informed that the service "Postage not paid" will not be available from July 1, 2019.
Service Postage not paid
With the postage not paid service, you can send your parcel without paying for the postage and the costs are paid for by the recipient. The recipient pays the delivery costs (the price of the postage not paid service) upon receipt of the shipment. If the recipient refuses payment (and therefore acceptance of the parcel), the parcel will be returned to you and you will be obliged to pay the delivery costs.