Months of poor internet performance; what will it take to get an actual repair?

Here's the deal, Cox.  The problem I'm having is a combination of 902MHz ISM ingress and an exceedingly poor gain structure. And probably an "over-subscribed node", but that's just a hunch.

It's not my modem, it's not the wiring in my house (I own an RF network analyzer), it's not downstream signal levels (8.1dB-2.5dBmV), it's not downstream SNR (>37.9dB). 

It is the Cox equipment and network. 

How do I get in touch with someone at Cox that knows what any of these words mean? 

I don't want another "tech" to come out and lop off $50 of Canare F-Conn, calling them "junk" only to have me go back and replace the radio shack grade F-conn's he installed in their place with the wrong sized crimp die.  I don't want to have to explain why a directional coupler is different than a power splitter. 

As a matter of fact, I don't want -or need- to see the Cox tech at all, because the problem is not on my property.

Who do I need to talk to?