UK flat Noise question?

So I’ve lived in flats around 10 years never had problems like this,

Moved in before Christmas and noticed I can hear up and downstairs a lot, like normal talking.

The upstairs neighbor has knocked twice threatening to go to the landlord about noise from my flat for example if flatmate raises her voice (I wouldn’t even call it shouting) and it has always been at reasonable hours. (NEVER AFTER 11PM OR BEFORE 8AM)

In Febuary he actually pounded on the door at 5aclock in afternoon because in his words he could hear a domestic and asked if she needed the police (she was on the phone getting a hard time from someone in work)

So my question is is he been unreasonable downstairs has never complained, to me because he lives alone and owns his flat and we rent seems like a power trip and is their anything I can do?

TLDR: flats have zero sound proofing, neighbor complaining of raised voices and threatening, anything I can do.

Thanks in advance 🙂