Sudden increase in home internet data usage

Hi there, 

I received an email on Feb/6 from Xfinity notifying me that I have used up 75% (or 0.9TB) of my monthly data allowance of 1.2TB. Yesterday night, I received another email notifying me that I have used 100% of my month data allowance, and I am now being charged $10/50GB for additional data usage. I live in a household with myself and my wife. We spend most of the weekdays at work and don't stream hours of videos or music Monday-Thursday.  We did not add new devices in February that would've consumed all the data. I checked my data usage overview on xFinity and February 2024 is definitely not making sense to me right now. I just don't understand how I used 1.2TB of data in 11 days, when my typical data consumption was around 400GB or less per month.  The only change since January would be upgrading my xFinity home internet services to a higher capacity service. My data usage trend is not in line with this month's usage and I want to understand why so I can avoid in the future. 

I reached out to customer support and chatted with an agent online, but told me that because I am not renting an xFinity router, there's nothing xFinity can support me with.  I read through the router rental program and cannot find information on xFinity denying to support a customer if using my own equipment.  This seems very unfair, especially when xFinity charges extra for renting your equipment.  Can someone please look into why my data usage is suddenly so much more and provide an explanation?