Thanks for the feedback.
The tracking ID for the eBay entry itself always stays like that number (it's used to access the eBay API and track changes made to the order).
As soon as the seller adds the tracking ID and tracking company, the app will add another status saying something like "Further tracking information was supplied" including the courier name and tracking ID of the actual shipment. This is then used to create a partial delivery so please check if that was added in the edit delivery screen (or if you have such a status message at all).
Unfortunately, many sellers I came across did not add the tracking information to eBay properly resulting in them not being available via the API. If all of the above does not help, please send a screenshot on how the order / tracking information looks on the eBay website to firstname.lastname@example.org so I can compare it to my results.