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I recently upgraded to a DOCSIS 3.1 modem and Gigablast and I have what is pretty clearly the textbook problem where an old analog filter on the line blocks channels below about 600MHz, preventing DOCSIS 3.1 from fully working and limiting my speeds to ~600mbps. I can log into the modem's built-in spectrum analyzer and see that I have great signal down to 600MHz, where it abruptly drops off. The modem status page indicates I am only connecting on 20 channels, and the remaining channels have a null signal level. The status light on my SB8200 which lights green for DOCSIS 3.0 or blue for DOCSIS 3.1 is lit green.
Despite all this, when I call Cox support, their "system check" says my modem is working "perfectly" and supposedly "will not let" them create the service call for the tech to come remove the filter. This should be trivial to address but I can't get it addressed.
Has anyone gotten a similar issue resolved? Is there a moderator here who could reach in and get this call scheduled for me?