How can the same tracking number be used twice for 2 apparently different stores?

Summary: En la discusión, m-lady pregunta cómo es posible que el mismo número de seguimiento pueda ser utilizado dos veces en dos tiendas diferentes. Sin embargo, las respuestas de twyngwyn y sandypebbles no ofrecen información adicional ni contenido, dejando la pregunta sin una resolución clara y sin detalles adicionales.

I bought 2 items (car mirror parts) from 2 different stores (both say AUS stock). First one was marked as posted and tracking said 'sent without tracking' but a day later, APost sends an email with tracking. Item 2 still not marked as posted a few days later - contact seller - no response. Next day item is marked as posted (without tracking) - contacted seller again for tracking, no response.

I receive item 1 and it doesn't fit so I sent it back. Today I checked ebay again for the second item and it says 'delivered' - Then I get an email from ebay saying 'package is now with carrier' and when I clicked on the tracking it is the same tracking number as my first item that was delivered - How is this possible ?? I contacted seller again, but no response yet.

I tried to make a complaint to Ebay saying item not received, but as it is marked as delivered it is not letting me do it - Please help