How Do You Deal With The Neighbors Slamming Their Door?

Closed wooden door of a home with yellow siding in daytime.

Oh my goodness….I am at my wits end and just don’t know what to do.
I moved into a fab new condo in July, but the nightmare started soon after.  My neighbors let their door slam when they come and go and it echos down the hallway and is LOUD in my place!  It happens numerous times a day and even guests to my place are like “what the heck was that?!”  I’m telling you – it’s loud!
I have asked them to please not let it slam, I mentioned it to the building manager, I mentioned it to their landlord – who also lives in the building.  IT DOESN’T STOP!
They come and go at all hours – like the other night I was woken up at 2:12 AM when one of them came home.  Apparently they must have forgotten something in their car as they let their door slam again at 2:15.  YES!  That is how loud it is, it wakes me up from a sound sleep!
Surely it must be loud in their place too, right?  Or are they so oblivious to it that they don’t notice?
My question to you is – what do I do now?  Turn up my TV?  That doesn’t work either, as I can hear the slam over the volume.