Cox's Failure to Support Gigablast

First off all I work from home and depend on a stable connection with good bandwidth... When the opportunity came up to upgrade to Gigablast I bought a brand new Arris SB8200 and upgraded my account.

From day one I never got full Gigablast speeds even when plugged directly into the modem with my laptop.  I even tested with another laptop and a desktop PC and none of them got more than ~650Mbps.  I was OK with that though because in my book that was good bandwidth.

Starting today I can't get more than 100Mbps at best... multiple tests using the Cox provided Speedtest app and website show download speeds as low as 5Mbps.  The connection also drops out all together intermittently for minutes at a time.  

According to Cox their system hasn't detected any issues or outages so they refuse to send someone to investigate.  I was willing to accept the fact that I'd probably be charged $75 for the truck roll but at least I'd have someone come out and maybe resolve the issues.  Unfortunately I'm not worth their time apparently.  I'm told that because their system doesn't show an issue they won't send a tech... Now, to be clear, I'm having to chat with this person using my Verizon mobile hotspot because my Cox connection was completely down but I still don't qualify for assistance.

This is absolutely the worst customer service I have encountered with my home services and refuse to pay $150 per month for service that isn't worth Cox's time to fix when it is obviously not working correctly.

Has anyone else had this happen?  What did you do?  Was it ever resolved?  Should I just change ISP's?

Thanks...

JP