Terrible speeds - Comcast not helping! Paying for 1G, getting <90mb

Help!  I've had Comcast out to my house twice and had calls with the regional tech manager.  My cable and all boxes check out perfectly fine.  My cable signal is perfectly fine.  I've tried calling support, chatting with the Xfinity assistant...  People 'open tickets', but weeks are passing and I'm not getting any answers or any help.

I'm pying for 1000mb service, and I at *the most* have not ever seen over 120mb, and typically I get under 60-80mb.  The techs have all said that my service and modem are working great.  They said the problem is with 'network' and they can't help.  

Does anyone have any way to contact anyone about this?