The Goq, a few questions, please.
1. In which city and state are the premises located?
2. Is this an apartment in a multiple dwelling (i.e. a building with four or more apartments)?
3. Are you the tenant? If not, what is your status?
4. Do you have a thermometer? Can you tell us what the temperature is during the day as well as at night?
5. If, by chance, you are in New York City, did you make a complaint to 311? If outside NYC, did you complain to the local government?
6. Have you told your landlord your apartment is cold?
7. Before this incident, what was the usual temperature in the apartment during the day? At night?
dvorak, I am a lawyer and I suggest you sit this one out.
Of course, lawyers are expensive, and it may just be worth it to let this slide.
Actually, legal advice is a bargain compared to the consequences of not getting legal advice. Better yet, if OP is in New York City, there is lots of free legal advice available for tenants in Housing Court.