address to mail a payment

why is it so hard to find an address to mail a payment? I am traveling for work and my mom needs her comcast bill paid,  She is 79 and cannot leave the house due to an injury, she doesn't have internet and not only did it take me 4 hours to set up the online access to her account due to someone else already having set up an account under her name, with the account number, social and phone number.  Yet, she cannot set up online access since she does not have internet.   Finally, get set up and cannot access the billing information due to a PIN that has to be mailed since I am not connected to her network, which again she does not have internet, so can't view her bill for 5 to 8 days.  Tried logging into my account to look at my bill but it will not give me a PDF of my bill because I am set up paperless. What!!!! I cannot review my bill in detail being paperless. How in the world does that make sense. So here I am asking for an address to mail a payment but does seem like they are forcing people to pay online