Read the forum guidelines
Up until May 17, the online usage meter page showed that my daily usage varied between 10GB to 25GB. However, starting on May 17, the usage meter has been claiming that my daily usage is typically between 90GB to 115GB. My current monthly usage (ending 7/2) will end up around 2TB if this continues.
I have only Internet service. My use of the Interment is light compared to many, as can be seen from the usage meter numbers prior to 5/17. There has been no change in the pattern of Internet use since May 16.
I've done the usual troubleshooting steps.These very high traffic levels persist even after I've shutdown/disconnected equipment such as laptops, desktops, phones/pads, an AppleTV, a LaserJet, and WiFI extenders (but leaving the modem itself on and connected). Also, the traffic level persists even after I've changed the SSID and WPA2 password for my WiFI net. All WiFI clients on my WiFi net are devices that I recognize and are under my control. I have malware detection; there's no evidence of any infestation.
I have no children that might do such things as falling asleep while leaving Youtube videos running all night, every night, as I know has happened to some.
My household is mainly Apple hardware; there is one Windows machine (but, as mentioned, the immense flood of traffic is in evidence even with computers off, hibernated, or disconnected).
On Thursday, I called COX tech support for help. The agent double-checked my type of service and my trouble-shooting steps. He walked me through use of the usage calculator in order to estimate monthly data throughput based on my use profile. He and I agreed that there's a huge discrepancy between the profile's prediction of data rate and the actual numbers in the usage meter (about a 5-fold difference). The agent decided to escalate my case to tier #2 support. That agent went over the facts again and decided that a 'traffic check' should be done, telling me that I should expect a call back with 24 - 48hrs with findings
Not having received any callback after 4 days, I called tech support yet again. That agent reviewed the case history and the information as above, and recommended that I should step up to the 'unlimited data' service plan for an additional $50 over my current plan. She seemed disinterested in any further troubleshooting, and was politely insistent on the service plan step-up.
I declined the service change...it seems untoward to buy bandwidth in order to accommodate what appears to be a technical problem. That's like installing a bigger gas tank in a car in order to resolve a leaky fuel line. I would think a better next step would be to analyze/categorize/typify the traffic flow itself. I seem to recall a past case when COX did that for me (years ago) and found an actual equipment problem. Even if only the source/destination of the traffic were to be identified, that could shed light.