Many thanks Fabo.sk .
The rule of the last carrier is funny in my case, as it means I'll have to deal with an airline I've never actively chosen to fly with (it results from an irrops). Also, they have probably never seen my lugage (I suspect it was not loaded on an earlier connection affected by the irrops). I understand this is how the system works, so I'll deal with them and see how it goes. And to be fair, they've treated me seriously so far.