Any Luck with Charter Replacing Cabling?

I live in STL MO where Charter is king. When I installed my new system (Roamio, 2 minis) last year, I discovered (after extensive troubleshooting) that MoCa worked on 2 of my cable connections but not all 3 - due to a bad coax cable - so I have had to run the Roamio wirelessly. Thankfully, it's worked great. Now, another coax cable has gone bad. I've put off calling Charter to come replace the cable because of all of the horror stories I've read on here about the techs not knowing what MoCa is or how Tivos work. But, now I can't delay any longer. After being shuffled between several telephone support personnel (who admitted they had never even heard of MoCa), I finally just asked them to send out a tech and to please make a note that this is a MoCa/cabling issue. I'm not holding my breath...

Anyway, here's my question: Has anyone had any luck in demanding that Charter replace their home's cabling? My coax is 17 years old! Since I doubt that the tech will know anything about MoCa or Tivo, I'm hoping that I can just get them to replace the coax to fix the problems. Am I crazy? Any other pointers that might help me to get up and running again (aside from re-wiring the house myself)??

Thanks!