Are AirBnBs illegal in Berlin?

I rented an apartment for a couple of months. I've dealt with some very shady behavior from the host over the past week, and after I denied her coming into the apartment, she now wants me to just vacate immediately (I've already paid for a whole month, and had planned 2 months stay).

I just started reading all these articles about how Berlin banned AirBnB due to the detriment it causes on the rental market. But I've also read that some hosts obtain a permit, and have a registration code in the ad. The ad had that code, but why would some hosts get that permit? I thought the long term rentals (90 days+) were forbidden since they're the ones that hurt the rental market? I booked 2 months and she said I could extend it. So that would make it an illegal long term rental. I've read that hosts also need a valid reason for the permit, such as being abroad. I picked this unit, because the ad said she lives abroad - I thought "great, then I won't have to deal with the host" - but she's actually living downstairs and is calling, knocking on my door, and spamming the doorbell every day.

How do I know if the place I'm staying in is illegal, and who would I report that to?