Dozens of disconnections a day

I'm nearing the end of my rope. For the past 2 weeks my internet connection has been experiencing dozens of upstream service interruptions a day. Prior to the problems developing, I had no complaints with my connection. I had excellent uptime and speed. Overnight, my connection turned into a hellish problem. I had a Netgear CG300D gateway acting as both my modem and router that I was renting from Cox. My devices were able to connect to the router part with no issues, but the modem would constantly stop receiving data. When I'd go look at the error logs, I would see a "Unicast ranging received abort response" message that would accompany each time it lost signal. If I powercycled the modem it could typically pick the connection back up, where I'd enjoy anywhere from 5-30 minutes of uptime before the error would reoccur and I'd stop receiving data.

There's no reason or pattern to when these upstream service interruptions would occur, though I could usually count on 3-6AM being the most stable parts of the day. After talking to support a few times and being told that a tech needed to come and examine the problem, I finally relented and scheduled a call for yesterday. The tech came in, said it was the modem that was the problem, and swapped my Netgear router out for a more "updated" (his words, not mine) Cisco DPC3825. Within an hour of the tech leaving the service interruptions began again. And now, the router part of the new gateway is unable to stay up when I lose signal downstream so when I go down, I get stuck in a loop of power cycling the modem --> laptop finds my internet connection, whether it's via ethernet or by wireless --> whoops! no signal from upstream, so router stops broadcasting. The online light of my modem flashes between yellow and green, then all the lights flash green, then they all go out and flash yellow, before attempting to reacquire a signal. Rinse and repeat.

I'm in an apartment building, and my router is isn't going through any splitters (internet only). For the life of me I can't find where the error logs of the Cisco gateway are hidden so I can't post those, but here's what the power and signal/noise levels look like when I'm enjoying the sporadic moments of uptime. I will be calling support again in the morning but this is extremely frustrating because 90% of my life (entertainment, communication, work, and study) involves being connected to the internet in some way and it's rapidly becoming a nightmare. ZIP code 24018 if it helps any.