Neighbour telling me I’m loud

Hey guys I’ve moved here to Frankfurt a couple of months ago. But I’ve been living in Germany for the last 6 years. I live in a nice neighbourhood in an apartment alone. I work 9-5 from office and then I work out in the gym everyday. So I usually am home from 8pm till 8 am on weekdays and on Saturday Sunday I’m home other than house chores, gym or hanging out with friends. And I do sleep around 10:30-11 max. I’m at least away 7 days in a month for work travel.

I host no parties at my place. Just a few times my friends have come over in the day time. But I usually play music in the background when I’m cleaning or cooking or something (not super loud) and I’m on the phone with my gf.

Today, the lady living upstairs messaged me that I’m too loud and she hears my calls and she annoyed with the music I play and she wants peace. Now keeping in mind that she has teenager who’s watching porn (that I can hear too) and she herself has sex super loudly which has woke me up a number of times in the middle of the night but obviously I didn’t message her.

Can you guys please help me understand how I should solve this issue? Also what am I entitled to according to the rule of law? What could be consequences of dealing with a reply to her with all of her facts that she’s oblivious of?