Here's the link again

Here is a link that might be useful:

Personally, I'd call Comcast and tell them to send out somebody else who knows what they're doing.

The installer should have put a tone on the existing coax, traced it out, and located it - a pretty simple and standard procedure. If not, he should have fished a new feed.

Running it across the room is very unprofessional and a potential liability - resolving it should not be your problem.

I forcast very low odds of getting a wall fish or very much diagnostic time on the prewired cable, unless you apply a bit of monetary "encouragement".

If you want a decent job, the cable guy is not the one to do it, they're not paid/cable co doesn't budget for anything less than a very basic job.

Cable co ran coax on the SURFACE on the front of my neighbour's house. You get what you pay for.

There are lots of clever ways you can retro cable wire. If the active outlet is on an outside wall, it's possible but not as easy. A media specialist or an alarm tech could do the job. Running under the baseboard is also a good option, you can either then fish it up into the wall, or install a baseboard outlet.