Is there a history of billing transactions?
Yes. You have access to your mailbox billing activity through your account. To view your billing records, simply go to My Account Summary to access the information.
Under this page, you can view how many scans allowance you have for the month, as well as how many mail items you can still receive for the month.
At the very bottom of the page, you can filter the billing activity by the month you wish to review as well.