Can’t pay my bill online or over the phone!

My xfinity internet is shut off and I’m trying to pay my bill. Xfinity’s website will not let me into my account it’s says access not authorized and I tried 3 different devices to get into my account and none work so I figured I would call the xfinity number to pay my bill and it doesn’t even give me that option it says I need to login to my account which I can’t because it won’t let me. I’ve been trying to somehow get my bill paid for 5 hrs now so I can have my internet turned back on. Please help!