Ah, that sounds dreadful.

Mention it again, maybe your T can talk to the neighbor. I'm sure he doesn't care more about the neighbor than you.
I'm at a community health clinic, and can hear EVERYTHING. People walking up and down the hallways. People talking in the next room. Babies crying. The plumbing when somebody turns on the water fountain. The phone has never not rung during session.
What can you do? I just try and tune it out.