JeRrYFaR wrote:The new connection is with a modem they added in the living room. My actual modem is in the office in the back of the house
Can you explain that? You should only have one "modem", or one device that coax connects to. It may be either a stand alone modem(like the TM3402) or a modem/router combo(AKA gateway) like the Panoramic CGM4331. You may have both, but only 1 device should provide internet. The TM3402 is a internet/phone modem(eMTA) so maybe they have your internet through the CGM4331 and your telephone through the TM3402? The reason this is important is because if you have your router(Deco) connected to the CGM4331 then you could be under what is called double NAT which can cause some issues. The solution is to either put the CGM4331 in bridge mode, or the Deco in AP mode. Which one you do depends on which one you want to be managing your network. If you have some forms of Cox TV(IPTV) or Homelife, then you want the CGM4331 managing it. Otherwise, probably better for the Deco to do it.
However if they SWITCHED you from the CGM4331 to the TM3402, that is different. Do you have any problems with your phone when you have the packet loss? Probably not loss of dial tone, but do people complain you sound like a robot or they sound like a robot? If so, then that isolates it to a Cox issue. Try posting your modem's signal levels. You can find them by entering 192.168.100.1 in your browser. If it asks for a login, try admin/password or admin/admin or try them blank. There should be a section with downstream and upstream signal levels. Post a screenshot.