HUGE Spike in Internet Data

There has been plenty posted about this issue in the last few years, but it is happening to me NOW.  I've been with Xfinity for YEARS and my usage has NEVER been an issue, NOW today with 10 days left in the cycle I am OVER the 1.2 TB.  That just flat out isn't possible.  It showed my iphone used 600GB before noon today.  It shows my  monthly usage at over 2.3 TB (usage data for individual devices is from my Google Home App for my Google Nest  system)  Xfinity doesn't give individual device usage, just total.

I've spent over an hour on the phone with the tech folks in Manila, first representative agreed the amount of usage in the periods claimed was NOT POSSIBLE and transfered me to Shawn.  He said, "I used that much data.... PERIOD"  I had too many devices and I should turn some off.  I TRIED to explain the disputed data amounts are NOT physically possible.  

As the post I've read, and there are many on this issue, none are current in the last month or so.  

Can someone give me some guidance, direction or support?  Xfinity's answer is just; 'you used that much data'.

thanks