Something small like that might be a good job for Capitol Hill handyman? Alternately you can probably purchase your own cable, protect the end with tape, and use the existing bad cable to pull the new cable through the wall...

Agreed - start with a handyman or try to do it yourself. I'm not great at this, but I've managed to pull a cable or two. It's not too hard, assuming there is some room in the wall. Google "how to pull cable". If you need a true home automation professional, I recommend Wipliance. They can fix your whole setup no matter how complicated, including hardware, electrical, etc for $$$.

Have had the same issue and thought about doing it myself and was told it was not hard but this was not encouraging - instructables.com/Repair-a-...
We were having some electrical work done anyways and the electrician was able to pull the cable through the drywall. Better off paying a professional :)