Thank you for your reply.
I have set the time on my ipad to the exact time of my time zone (via time.is), with an accuracy of approx. 500ms. Now a strange thing happened: instead of showing "wrong key" or something like that, the error message now is "Sorry, we couldn't find your code. Try again?" (website in english) - on the german website version "Wir konnten deine Seriennummer leider nicht finden. Erneut versuchen?", which, strangely, translates more to something like "We couldn't find your serial number. Try again?".
Now i am pretty sure that my account name (derived from e-mails i have gotten from swtor a long time ago, which mentioned my account name - because i have forgotten it in all those years) is correct, because if i enter the wrong combination of account name and password, i get the error message "LOGIN FAILED". If i enter my account name and my password, it asks for my security token instead, which means i have the correct combination of account name and password.
Again: Is there any other method of contacting support? Or maybe support can contact me via private message here or whatever... it gets increasingly frustrating that no option mentioned in support articles work and the only (!) solution provided is "call support". Besides, how would deaf players handle this?
But nevertheless, my frustration is not directed at you, EA_Kipling, i appreciate your effort to help me.
EDIT: This authenticator can still be used, right?: https://itunes.apple.com/us/app/star-wars-the-old-republic-security-key/id996685033?mt=8
Solution: Turning my phone off of "Airplane Mode" is what worked for me.
