Because this is for a mail box and we do not know if it is really your mail box or if you are someone up to something bad, we cannot in good faith help you get into the box.
Please ask your building management for a new key or call a local locksmith who may have the legal right to open that once they prove it is your mail box container.
If you wish to ask some hobby lock pickers who are closer to you, please visit the German language KOKSA forum
https://koksa.org/index.phpBest Regards,
Forum Management
