Data usage validation

I have been observing higher data usages since May 2025 without any changes in our daily routines. At the end of Aug, I was back working full-time outside the house and expected less data usage the following months. However, it's not observable as Sep and Oct, the monitoring system indicated almost no data used, which is inaccurate. In Nov, the data usage is back on high again almost at the cap toward the end of the month, despite the facts that I spent full-time hours working outside the house, compared to pre-Aug when I stayed in the house most of the time.

I have called customer support a few times without any actual resolution. An agent did mention that the system couldn't see my devices connected even though multiple devices were using data at that moment. The monitoring seems really unreliable; I need help with the validation as this month (Dec) is on track to be over the cap again. This is really limiting our data activities at home.