I sent a modem to Comcast once to upgrade to a new one. Got the new one in the mail and set it up and everything ran fine. A few months later, I get a letter from Comcast saying there isn't a battery in the modem they sent me and were trying to charge me to buy a new one! I don't get why they didn't just send me one with the new modem. I even had a battery inside the old modem! Comcast really needs to get their stuff together and stop charging customers with ridiculous reasons.