I am in that same boat. Been going on for 7 years. I finally wrote to the FCC and started getting some response from Cox. they sent 2 of their special field agents to my home after completely fixing everything in my neighborhood. They then told me they would lend me the Panoramic modem-router and if it helps I can rent it for $10 a year. LOL Sure and give them an extra $120 a year? I could buy a new one for that. I am not that crazy.
Anyhoo, I have had this several weeks now and my internet just keeps getting slower. I subscribed for 30 Mbps and on this computer (wihich is not my fastest) it is registering 140-525 Kbps. Before they left they tested (but on "their" site. LOL and it was somewhere in the 20's Mbps
I must be an idiot as I keep shelling out the bucks every month to COX.
They "fix" something but not for long. Give it a few days and the problem is back and sometimes even worth.
You just can't imagine how much of my time I have given up between phone calls and waiting for their support guy to arrive.