Hello Roland,
Thanks for the info. Unfortunately, I left Switzerland yesterday thru Widnau ( I think) and the bus didn’t stop. I guess it’s the weekend and the zoll is closed. If I had known, maybe I can get the custom stamp at Zurich bahnhof or Buch as you suggested.
Anyway I’m going to try going to the Swiss Embassy in Vienna to see if they can help me.
I’m sure that there’s people in the same situation as I am now. I’ll post an update.
best regards,
HT1