I know there a lot of upset customers, and tier 1 support telling you to reset your modem or doing it remotely then saying all is well. Only to have the problem return. Either COX over sold a node or...
It is important that you clearly document the problem before filing a FCC complaint. Signal levels, packet loss, event logs, etc. It's usually good to have a technician or two out to troubleshoot the issue as well. Sometimes it takes a few tries to get a Cox technician who has the tools/training/time to troubleshoot advanced problems like noise/ingress. The FCC complaint is a good route to go when all else has failed not the first place to turn. Not all problems are loose connections or bad amps. There is a lot in-between that can go wrong.
Yes when it's a qualified tech! Cox has contracted third party companies who don't even use proper meters to diagnose problems. When problems are intermittent like time or temperature based when amps stop functioning at night when temperature drops. Also tier techs buy off the tickets like they fix big problems, that leaves customers having to call back. I've personally experienced all these situations. Cox needs to own there faults and fix em. Customers need to pay there bills that's how this works if there is a problem Cox should fix em or give free service them they can give customers the run around all they want with there remote modem resets lol.
Most electronics work better when the temperature drops. However, techs can request a 24 hour log/testing be done on a line, and see if overnight there are issues. It could be ingress coming from something happening overnight that isn't happening during the day, like a ham radio operator talking to their friend at 2 in the morning.
Tier 1 support these days is pretty bad with most/all ISP, not just Cox. You should try Comcast support sometime. I have heard horror stories on Reddit. The problem is in-house Cox technicians are a lot more expensive then contractors, so it is a necessary evil. The important part are things should be escalated to Tier 2(CAG) or a in-house technician when the contractors can't figure it out. That's where the system seems to break down and the FCC comes into play.