Letter & log
When talking and notes no longer help: a factual letter to the property management – and a log that shows it's not a one-off.
General template, not legal advice. For questions about rent, it is worth getting advice from the tenants' association (Mieterverband/ASLOCA/ASI). If you want to pay your rent into an escrow account, you must announce this in writing beforehand (Art. 259g CO).
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Log
Record every incident straight away – with date and time. A factual log is more convincing to the property management than any account from memory. The entries are stored only on this device.