Thanks for the flowers :)
I am having trouble formatting the “title” of each column.
Please set a "Text on top of the items" in the respective question, which you can set in the "Header" tab.
do you have any ideas how this could be made possible
It depends on how much anonymity you want to provide. If thinking a bit about this concepts, its a continuum between "obviously a specific person" and "would cost billions of Euros to find out who it was" (there can be no 100% security in real life).
An option that would be far on the anonymitiy side is: Give the people a random code in the first place, and ask them for the code in subsequent surveys. The obvious risk is that people may lose their code. To avoid that, psychologists sometimes prefer a "personal code", see Request of a Personal Code. Given an appropriate sample, this is still far enough on the secure side to be considered "anonymous", usually.
I would very much appreciate it, if we could speak on the phone.
Yes, I hear that quite often. And I really like talking to people. The point is, that a 24-hour day just does not have enough time for such luxury. And then, there are some more jobs to do (software development, caressing servers, ...) beyond support. If you like to talk on a professional level to another researcher, better contact my alter ego who's working at the LMU during business hours. He may be available for a talk :)