Clearly there are people on this thread that have never had the frustration of dealing with Comcast...yes, they make mistakes - and if I made the number of mistakes they do, I would have been unemployed a looong time ago. They make mistakes because nobody there talks to anybody else in other parts of the company or really cares about the service they're providing or whether the advice they're giving is right or wrong.
When I moved a few years ago I bought a TiVo because the Comcast-provided DVR was so loud in my bedroom that it was actually waking me up at night. To use the TiVo, I had to get a CableCard from Comcast. I had an AV guy doing some other TV and networking work at my house who said that he could install and set it up, but wasn't sure whether Comcast would just provide the CableCard or require a service appointment. So I called. CSR on the phone tells me with absolute assurance that I can pick up the CableCard at a Comcast office, I don't need to schedule an appointment. I ask him about 10 different times, even ask him about the specific office I'd be going to and he keeps saying yes, I know exactly what you're asking for and they'll have it and you can just pick it up. So I drive an hour RT out of my way after work to the Comcast office, pay to park in a busy area, wait in line for 20 mins. once I get inside...only to have the lady tell me that no, they have no CableCards. In fact they've never had CableCards, she has no idea why anyone would tell me that I could get one there, the only way to get one is to schedule an appointment and have the tech bring it out.
They have gotten marginally better though...when I moved to my old house 10 years ago and scheduled them to come out and set up internet, the tech showed up 8 hours after the end of my appointment window without apology (I'd been on hold for hours trying to figure out where he was and had been told by Comcast hours earlier that he was "literally on his way to your house right now"), yelled at ME for "scheduling an appointment on a busy day," had a young child with him who he left sitting in the truck in the dark outside, and ultimately refused to set up internet that day because he "didn't have time" so I had to reschedule the appointment. It took me weeks to finally just get internet installed.
When I moved a few years ago I bought a TiVo because the Comcast-provided DVR was so loud in my bedroom that it was actually waking me up at night. To use the TiVo, I had to get a CableCard from Comcast. I had an AV guy doing some other TV and networking work at my house who said that he could install and set it up, but wasn't sure whether Comcast would just provide the CableCard or require a service appointment. So I called. CSR on the phone tells me with absolute assurance that I can pick up the CableCard at a Comcast office, I don't need to schedule an appointment. I ask him about 10 different times, even ask him about the specific office I'd be going to and he keeps saying yes, I know exactly what you're asking for and they'll have it and you can just pick it up. So I drive an hour RT out of my way after work to the Comcast office, pay to park in a busy area, wait in line for 20 mins. once I get inside...only to have the lady tell me that no, they have no CableCards. In fact they've never had CableCards, she has no idea why anyone would tell me that I could get one there, the only way to get one is to schedule an appointment and have the tech bring it out.

They have gotten marginally better though...when I moved to my old house 10 years ago and scheduled them to come out and set up internet, the tech showed up 8 hours after the end of my appointment window without apology (I'd been on hold for hours trying to figure out where he was and had been told by Comcast hours earlier that he was "literally on his way to your house right now"), yelled at ME for "scheduling an appointment on a busy day," had a young child with him who he left sitting in the truck in the dark outside, and ultimately refused to set up internet that day because he "didn't have time" so I had to reschedule the appointment. It took me weeks to finally just get internet installed.