We like to use a real answering machine because it plays out loud while someone is leaving a message. The Xfinity voicemail was a good backup as it would record messages if we were on the phone (so the physical machine couldn't pick up).
As of a few weeks ago things started going haywire. People would tell us they called, the phone rang four times and then went silent. So when I tested it I realized the greeting and beeps weren't playing for the caller but if the caller happened to stay on the line our physical machine would still record the person!
We just assumed it was the machine's age so we bought a new Panasonic set and it's doing the same thing! Rings four times, no one hears the greeting or beep, but it will record the caller if it senses any noise or conversation.
I have the machine set to answer at 4 rings and have xfinity set to answer at 8 rings .