Upgrading house modem cabling

My current house modem cable is 20 years old  Comcast internet tech came to house and said techs don’t go in attic to replace cable anymore. Tech stated he would send my request to a third party who would. That never occurred. I rent a Comcast 1gig Xfi modem and 1gig speed. I want to hire/purchase someone to lay upgraded modem cable in attic to connect to new Comcast box outside on house  wall. Comcast has already ran new orange cable from pole to house box this past year. I have spent hour on phone with Comcast and no help. Please advise. Thank you.