That's where your wrong.Anyway, if your house/apartment had sh*tty wiring to begin with that could be the cause. Maybe not necessarily comcast�s fault.
If they send a technician out to setup your internet/cable, it is their fault. They can easily check to see if the cable is getting a bad signal w/their portable oscilloscopes and replace them if need be. This happened to me with 4 technicians and the last one finally got it right and he's the only nig I gave a tip to.
This also f*cking happened to me: the signal from the line into the house was so weak that we couldn't keep a steady internet connection. Comcast's own wires were f*cked up and it took me getting my neighborhood to call them b*tches up and get it fixed.
They're basically like any big business in America; looking to f*ck the people over for their own profit because they know they can.