Looking for a customer service phone number to contact to see if I can upgrade our wireless gateway router that is no longer supported. We have had this gateway for over 5 years. All I get is the go-around with the live "Chat" service Comcast has. Can I just make an appointment and take it into a local store and ask them for an upgrade? I'm not willing to drive to the local store miles and miles away to find out that I can't upgrade it.