Yes, that might be the most productive way to handle it. Agreed. I can speak a little German but that would only result in a comical communication exchange.
I would just be sure not to attempt to ask for any information that might be perceived as insider information. That would shut the comm down. I think that asking if they have a business arrangement with CTKH is fair game. Also I would ask if there is any PR or information in the public domain that might be available to describe the business activities between the two parties. Even if it is in their language. My guess is that they will simply refer us to call CTKH. That seems to have been the SOP for many years including the TA. I'll defer to any lawyers here on this board.