Microphon trouble with refurbished samsung galaxy s9

Unfortunaltely I have big trouble with my freshly recieved samsung S9. Phone-call partners can only understand me, when I am screaming. I tried all depending settings and I use so far no bluetooth devices for calling. During voice recorder sessions I have the same trouble: only quiet scratching with some barely understandeble words.

HELP What else can I do?
I didn’t had this problems on my first self installed /e/ phone samsung galaxy note3