Called my cell phone several times, sometimes leaves a messages saying "This is ComCast calling to ask your opinion in a customer survey about your recent installation process" and I have called the number back and get an automated message saying "Hello, This is ComCast, we'd like to confirm your installation appointment and it gives some random date/time for tomorrow morning."
I returned this call. I did have an appt set up for service. An automated answering machine verified the correct date and time without any input from me. So it seems like a real #.