how do I cancel service

I have always called them in the past, but you may be able to do it online. Just know they don't want you to cancel they tried to get me to switch it mine to a friend rather than cancel I told them I would not do something as terrible to my friend. When you call you just have to be very adamant that you are cancelling your service good luck

Call the number, 800 comcast and tell them you want to cancel.