+1 to add this tracking provider.
The page to track&trace is http://vaspexpresso.pt/TrackTrace.aspx
(only available in Portuguese at the time of this post).
The Iberian Amazon (Portugal and Spain) (amazon.es) is using a third party called Celeritas (https://celeritastransporte.com
) for returns logistic. Celeritas seems to be using VASP Expresso and its collection points network brand called Kios (http://kios.pt/servicos/kios-express/
) in Portugal. When an Amazon return is sent through these collection points, the customer is given a tracking number issued and trackable by VASP Expresso.