I booked a rental car online from Thrifty, to be picked up at VIENNA MAIN RAILWAY STATION, AM HAUPTBAHNHOF 1 (at least that's what the reservation voucher states).
The problem is: Thrifty does not list any pickup-location at this spot in their full list of locations (only Vienna Airport is listed), and the train station's official home page states that only the Avis, Europcar, Hertz, and Sixt companies operate local stores there.
Where do I have to go to pick up my car?