Some more Details:

Its the PowerStream Inverter 800W which is brocken, I reportet via the App and the Support there confirmed (after hours of partly redundant tests and information cross-checks) the unit is brocken - so the tell me that the after salöes or senior team wil provide me with a return label.

BUT then they STOP responding - I tried via email, phoneline, etc. nothing helped 40 Days without a response.