That might not even help.

I have been in similar situations. And I also was hit by the odd French habbit of shutting down Paris Nord for Lunch.
In the past there was a small kiosk at the head of the Thalys platform, where in case of a delay you just presented your ticket, and got the "HOTNAT" stamp. You of course needed to have your previous ticket endorsed, so the person in the kiosk could verify that indeed you were late.
This kiosk has gone now, so now you need to discuss matters with a conductor. The last one I talked with seemed to be under explicit instructions to pretend there were no other railways in Europe. What I in the end gathered is that if you want to be able to be transferred ot another Thalys train you must make sure that the conductor of your delayed train calls ahead to the central dispatching. And be prepared for discussions.

All part of a grand master plan to destroy railway travel I assume.