Data usage incorrectly reported by Xfinity

Hi

Xfinity just notified me that I used over 900GB in less than 4 days of the month. 

This is totally incorrect. I had not used that much any month in the past 12 months. I have not changed usage pattern or had new device, and all the sudden I was told I used over 900 GB is less than  4 days, and continue to add 10 GB per hour. 

Please correct your issue ASAP, and I should not be responsible for your mistakes. 

Please let me know how you plan to fix the issue. 

Thanks