My problem is finally resolved. My problem started July 2. I had numerous calls/texts to COX and at their suggest, bought two new cable modems and one router. The second modem is COX panoramic modem. Cox sent repairman twice. The second repair man asked me to disconnect the amplifier (I only knew this box connecting input signal, plugged into AC and output to modem) initially installed by COX when they changed system. Now may download speed is alway more than 140 Mbps using COX internet speed test, never being so far before. Now I just hope that COX will give us some discount for our loss of internet use, not to mention the anguish and frustration that my family suffered.