Here is a picture of the overlay: https://p.twimg.com/AvuHb1uCQAADaOX.png:large

I got this too!  The message is actually being injected into the HTML via javascript.  But how?  I checked on a few computers, and they all have the same problem.  It's not even all the time.  Could it be possible that my router is infected?  I also noticed that I cannot access Comcast.com from my house, but I can at work just fine.

I didn't get a call from them, but I did call the number just to check it out, and I got an automated message that said that I should call back during business hours, and that the organization is Media Link, an authorized "Comcast distributor".  What the hell?

A friend's computer displayed a pop up claiming to be from Xfinity / Comcast.  The popup claimed there was a problem with the internet access and that the user should call this number.  Phone scam + malware!

I am having the same irritating box that won't go away..  I did call the number but since my internet is with my rent they got nothing from me...I wouldn't have given them anything anyway because it seemed weird to have a 3rd party be in charge of these account matters.   And yes I have noticed the number has changed a bit from yesterday.

I had the same issue as the initial poster above.  Calls from 2 people -- each time it felt fishy, so I ended the call.  Now I'm getting the message on my computer and wondering what the deal is ... I called COMCAST after the calls and was told that there was no issue -- if that's the case, why the messages on the computer?  Do I have some kind of virus?

Do Not call the 8554609707 number as it is not Comcast/Xfinity per the 1888-COMCAST or 1888-XFINITY. By the way it was over 48 hours when I first reported it and it is now 72 hours plus with no action to resolve!

This is a call from someone posing to be an Xfinity/Comcast rep who stated that they needed to verify that I had internet service as I had not been paying for it.  "We need to remedy this situation" and then asked if he had permission to access my account.  I said "No" as I was immediately suspicious since they called me and they would already have access to my account if they were legit.  I told the so called rep that i would check it out myself and called the 888-Comcast or Xfinity number myself and they said they did not make any such call and it is probably a scam.  A few days later, a message is appearing on my screen telling me to call 8554609707 to verify my service so now I guess this is a virus but am concerned that they have now hacked into my account.  I have called Comcast several times and they claim to be working on the situation and to give them 24 to 48 hours (which has not passed).  However, the message is still popping up on my screen and I have not received a legit call from Comcast about the progress of this situation.  By the way, when the bogus rep called, a different number was on called ID and it did not state it was Comcast.  GRRRRR!!!!