final bill issues due to multiple accounts and account switching not working

I just switched from a post-paid Xfinity Internet + TV service to Xfinity NOW Internet. I received an email with the amount of my final bill for my post-paid Xfinity service and a link to view the bill at https://customer.xfinity.com/#/billing/brite. I tried viewing my final bill there and used the link in the top right corner to switch accounts (the default account that I'm logged into when I visit that page is for my new Xfinity NOW account) but it keeps taking me to my prepaid Xfinity NOW account, not my previous post-paid account.

How do I get my final bill? Can you send an electronic copy of my final bill to me via email attachment as a pdf?

Thanks in advance.