COMCAST Brian L. Roberts Was charged over 100$ for installation fees I was never told about. 1st Comcast bill = 448$!! Internet

Fast forward to Dec 7th. I still had not received a bill and was starting to worry. So I called up Comcast and to my dismay, having used these services for less than a month, was told I owe Comcast 448 dollars and change. Needless to say I was in shock. I am a Special Ed. teacher in New York's inner city. I could not afford this bill, especially when I was not even warned it was coming. I had no way of preparing because I was not told that I have to pay a month in advance or I had to pay over 100$ for installation fees. 

These fees are ridiculous. I live in a condo and the man who sold us the condo also had Comcast. I was charged for activation fees? 29.99? All the outlets and wiring were there already. The Comcast rep named off other charges that I was never informed of either.