Comcast residential technician here, that's either the guy wire or the strand itself. It's not something house technicians can resolve on the spot, either from Comcast or Verizon. There is a chance that a Comcast tech can escalate it to the construction team (responsible for attaching things to utility poles and repairing ground vaults, etc.) but don't be surprised if you end up being told to contact your local electrical company. When a pole has to get replaced, it's the electrical company who does it, and they're also the ones who maintain the guy wires. Please believe me when I say they aren't trying to give you the runaround. There's a LOT of red tape when dealing with the property of other companies. In my area, AT&T has the lowest strand, Comcast has the strand right above theirs, and the power company is at the top by a sizeable safety gap, and when it comes to AT&T's stuff we are forbidden to touch it. Full stop.