Brief update:
Since no payment had been made yet, I went to a lawyer for the first time in my life... :-O
So I googled for a lawyer specializing in tenancy law, and lo and behold, there is one only 300 meters from my workplace. I went there spontaneously and wanted to make an appointment for an initial consultation. He immediately called me in and listened to my brief explanation. Then he kept my documents with the note: "I'll take a look at this"... but he also gave me some documents to sign (power of attorney, etc.).
I dropped these in his mailbox on Monday. Yesterday, I inquired by email whether he had been able to get an idea of the situation.
In response, I immediately received by email a copy of a document he had already sent to the landlord...
It roughly states:
- that he has so far not prepared a "proper accounting of the rental deposit" and should do so. That we have already requested this from him several times, but he ignored it. He is therefore in default and has to pay the lawyer's costs (approx. 150 euros). If he continues to refuse, it will become significantly more expensive for him.
I was shocked at first... after all, I went to the lawyer and asked for an initial consultation. That he sends the landlord such a letter right away... phew... especially since I still don't know what the chances actually are...
I will try to reach him by phone...