Weird data usage issue - Please help!

I've been a long time Xfinity internet customer. I added another Xfinity internet account for another address at the end of April this year. So now I have 2 separate Xfinity internet accounts for 2 different physical addresses. I'll call these Account 1 (original) and Account 2 (new).

Account 2 was created under different email address but same phone number as Account 1.

At the end of May, I got an email from Xfinity for Account 1 saying that I was approaching my 1.2TB data limit. I thought that was strange because my usage pattern hasn't changed. So I poked around and saw that my data usage showed 0 for month of May for Account 2. 

I'm guessing that for some strange reason, my data usage for Account 2 is being added to Account 1. I think this explains why data usage is 0 for Account 2 while data usage increased for Account 1.

I contacted Xfinity customer service few times but they don't seem to know how to fix this.

Any help would be greatly appreciated!!!