Thanks for your replies and this explains it well. It is still a bit confusing that some of the Hampton's would show up on the Hilton search but then show as sold out. Also neither Hilton (via chat) nor the hotel could explain it to me (and I did have somebody to translate so it was not a language issue).

Not a big deal, was more curious what is going on. The Hotel itself was pretty decent and more or less similar to a Hampton Inn in e.g. Germany with a bar / restaurant. Gym also was ok (smallish but good enough) and breakfast had a cook for eggs. Considering this was in a small town and compared to our standard hotel there it was a step up.