Never showed up: How do I contact Comcast Construction?

Canm anyone tell me how to get in touch with Comcast Construction in or near San Jose, California.  (I'm in Los Gatos).  Here's the (incredibly frustrating) story.

I had Comcast Business Internet installed three weeks ago.  Techs who put it in were blantantly dishonest about the signal strength--which, as it turns out, is insufficient to boot up an X1 cable box. (I learned this when I had my own network tech check the signal strength on the incoming line). Since then, I've had a dozen phone calls to Comcast and four onsite visits by Comcast technicians. The last tech who came out (two weeks ago) confirmed that I needed to have RG11 cable run onto the property, down a pole, and then through an underground conduit to the building.  The conduit exists and currently contains an RG6 cable.  It is clean, accessible, and no digging is required.

That tech put in an order for Comcast Construction to come out and drop the new cable, which was supposed to happen yesterday (August 28) between 8 am and 8 pm.  At 7.45 pm I hadn't heard anything from Comcast.  I called Comcast Business and was told the ticket was still open and I should expect someone yet that evening. Obviously, that never happened.  This is apalling customer service--to not show up and fail even call the client.

Another two hours on the phone today.  I learn that it's impossible for a customer to call Comcast Construction directly.  (Dumb.  Why didn't I get an email confirming the construction work with a phone number to call Construction Dispatch if I had any questions?)  Today, call center rep says he'll send an email to Construction--tells me he, too, is unable to reach Construction directly by phone.  He offers me no explanation as to why Construction didn't show up yesterdays  and no confirmation as to when they'll show up in the future.  Just promises to send an internal email.  He does offer to send another tech out to do "an assessment."  I tell him the situation has already been assessed on previous site visits--hence the work order for Comcast Construction.  What I need isn't another assessment but a rather large truck with a ladder and plenty of RG11 cable!!

Phone rep also said his records showed an aerial drop to my property rather than an undeground run.  I told him I had corrected this misinformation when I talked to one of his colleagues on the phone a week ago. In addition, I had shown one of the onsite technicians the underground run.  Obviously no one bothered to update Comcast's records.  Again, very bad form.

So here am I after three weeks with a non-working cable box and not enough signal strength to run my wi-fi access points or do video conferencing.  I've been tweeting the saga to my 26,000 Twitter followers--but their sympathy isn't going to get an RG11 cable installed.

What to do now???