Ultimate stereo nightmare

I have a complex stereo system, having accumulated many various components through the years. I also have an impenetrable jumble of wires.  Until now I’ve been able to deal with problems that arose. Now that I am elderly I can’t easily get down on the floor to assess things. I bought and installed new very expensive speaker cables (Audioquest Robin Hood), and subsequently found that my right channel was not working. After switching cables, the right channel was still not working. So the problem is somewhere in the system.  I don’t know if it’s a loose cable or something else and have no way of tackling the jungle of wires to check it out. 
I hired a company that claims they deal with these things, but there’s such complexity I don’t know whether they can deal with it.