Hi Raymond - To contact a member, click on their username (it's a hyperlink), and then click on "Send a message to this user". You can then write a message. Ziga is very good with his mail (I have done many trades with Ziga) and he would have registered the letter straight away when he receives it.
Please remember that COVID is still causing delays with mail services around the world, so mail may take longer than normal to arrive at its destination.