I live at my grandparents house and their 35 mbps dsl line isn’t doing it for me. So i got a xfinity subscription since there was already a box on the side of the house from previous owners. I want to put the router in my room seperate from their network. When their router came in all 3 coax outlets in the house failed. Just orange flashing light on the xfi box indefinitely.

I noticed cable TV still worked on the coax if you plugged a TV into them but not internet so I did some investigation in the attic and as I thought all of the coax cables going to the different outlets were going into a large antenna in the attic and not to the xfinity box on the side of the house. I noticed one unplugged coax cable going in the general direction of the box, it’s black instead of white like the 3 going to the respective wall outlets, I wanna say thats the coax from the box and the splitter up their was originally used to connect all 3 of tbe white coax but the attic isn’t completely traversable so I can’t follow it.

So before doing anything up there I checked the box outside and plugged the router straight to the box. I had a outside power outlet so I said why not.

But the connection still failed. Which means all of the wires in the attic aren’t even the problem right? There’s a problem with the ground line on the street? So I have 2 questions:

A. If I call someone from xfinity to show up and the problem is on the outside of house will I still have to pay for the repair? I feel like I shouldn’t since it’s a problem outside our property.

B. I really don’t wanna deal with the cable mess in the attic, and my grandparents seem opposed to me messing with the antenna. So could I make my own coax line from the box and forget about the attic one and run it around the house through the window of my room straight into the router?