cable not working when I purchased my own modem

I installed a Netgear modem and a mesh wireless system today. Everything checked out as far as being compatible with Xfinity. Internet works fine but now the cable TV isn't working. Customer service does not seem to care at all. They have hung up on me twice after transferring me from department to department. The "issue" seems to be that I don't want to use subpar Xfinity equipment to manage my network. Anybody have any issues like this that they were able to solve?