Are you using a separate / stand-alone router hung off of a combo Comcast supplied gateway device that is not in bridge mode ?
Describe in detail your network equipment / setup / topology. Include all makes and model numbers.
I’ve talked to multiple Xbox Experts and they say that you guys are sharing my IP with another customer to cut costs? If it’s not that I need to know what it is.
Just need to add, no offical XBox representative worth their salt would tell you this nonsense. You can't have the same public IP on two different devices, that's like two different homes sharing the same mailing address.