New neighbours are out of control, landlord turns a blind eye?

[user]

I live in an apartment block. Recently the apartment bellow me got sold and new neighbours moved in. They started to repair it - nothing wrong with that, I know. But I suspect they are removing supporting walls and that is forbidden, because the construction of the whole building can be compromized. I know how the apartment looks (because mine is the same) and there is absolutely nothing that needs to be drilled for THREE WEEKS. That's the amount of time they have been drilling.

Now, the noise is one thing, but what bugs me is that our landlord is turning a blind eye to it. It is forbidden to remove supporting walls, and yet she stays quiet. I threatened her that if she didn't do anything, I would refuse to pay my monthly building tax to her, because rules should be for everyone. She said she'd talk to them. And, here they are, still drilling away...

What can I do? Talking will do no good - obvously, even the landlord can't convince them.

[RAYN]

Is it possible they are building additional things in the room, such as built-in cabinets, furniture, or vanities?