For the TC75 right now I am afraid it looks like the options are limited. The best suggestion I have is to use the Google device manager (https://www.google.com/android/devicemanager) and log in with any account you suspect may have used the device previously to see if that account is associated.
If that does not work then you will need to contact support as it will likely be a back to base repair.
This is a scenario we are working on improving for the future but for now I do not believe there is a better option.
thanks for your fast reply that's great ...
hm hm rather boring ...but i try to ask to my colleague who has configured the accound google ...
have a nice day with android