Why is the chat giving us the run around?? Unable to contact Comcast is unacceptable..

Comcast is giving no customer support right now why???  I cancelled my services and sent back all equipment with a receipt sent to me and still receiving bills on top of bills instead of final bill...How are we supposed to find out what is going on with absolutely no customer service...Chat says sign in and I am already signed in..so you try and sign in where they direct you and it closes and you go no where over and over again...Why and how do we contact you?????