Apartment Guru: Where's the Heat?

Dear Apartment Guru,

I am a college student in Boston and I live in an amazing apartment - two working fireplaces, a clawfoot bathtub - you get the idea. Our troubles started in the winter when it was time for the heat to come on. Whatever they did to alter the heat from the whole house to work in the individual apartments, they didn't do correctly. One day it was 95 degrees and we would have to have all the windows open in the dead of winter and the next day it was 50 degrees. The management company came out three times to fix the problem but their "fixes" only lasted a few days.

After more than 6 weeks of this I finally went to the Boston College law library and looked up the tenant laws. From this I drafted a letter including the various codes and laws and told them I was well within my right to stop paying my rent as not providing a safe and habitable living environment and working heat was a breech of implied warranty. I mailed the letter. I received a call from a secretary at the management office who is as dumb as they get and had no idea how to respond to my letter. (I found out that she was fired not too soon after.) Finally, I stopped paying my rent. During this time, we experienced a huge blizzard and you guessed it, lost our heat.

We hunkered down with 10 layers on, all the doors shut to the living room and made as big of a fire as we could make. The management company threatened our co-signers (our parents) because we weren't paying rent - but never went after any of us legally since we were perfectly with-in our rights to stop paying (I checked with a lawyer friend who moonlighted as a bartender at the restaurant I worked at). Now we want out of our lease, which isn't up until September, but the management company is saying no and continuing to threaten legal action. What can we do?

-Just Starting to Thaw Out