Does anyone else hear that ringing?

I live in a old, refurbished building downtown. I have one of four apartments located on the top floor above a couple area businesses. One is a beauty salon and the other a credit/loan office. I like the fact that I live downtown and in a business district, it feels artsy and big city. I like parking on the street and watching main street parades from my kitchen window. I don't even mind the smell of nail polish remover in my stairwell.
However, this weekend has begun to take the shine out of my unique living conditions. As with most apartments, walls here are not built to keep out sound. I think budgets overrode comforts. I can periodically hear my neighbor's tv or the ringing of the telephone downstairs. This is in no big deal, something I can easily overlook as I'm sure I make noise in my day to day life as well.
Yesterday afternoon the credit/loan office's phone began ringing. I heard it and waited for the person on the other end to realize the office was closed, that there would be no answer and hang up, once again leaving me in peace. But the ringing never stopped. And I mean NEVER.
A couple hours into it, I called my landlord and left him a message. I had to leave my house just to quiet my nerves for a few moments. Luckily the tv drowned out most of it and I could make it through the evening.
Finally around 9:30 I was growing desperate for some reprieve. I tried the phone company - no answer, it's a weekend. I called the non-emergency policy - they said it didn't fall under their responsibility. I tried my landlord again - he didn't know how to get ahold of his tenants during weekend hours. I tried the security company whose sticker was on the front door - it was an old sticker and the office was no longer one of their clients.
Around midnight I turned on all the fans in my apartment (three, including my air conditioner) and positioned them in the noisiest way possible and went to bed. The fans helped and I slept through the night.
But I woke up this morning to the incessant noise. And it's ringing in my ears as I write. Does anyone else hear that or am I going crazy?