You certainly can. When you first signed up for your My PC Backup subscription an invoice would have been emailed to the email address you signed up with, please be sure to check your SPAM and junk folders.
You can also view account billing history and any previous invoices by logging into the Control Panel on the web app and selecting 'My Account' on the top right of the page. Scroll down to the table titled 'Subscriptions & Billing' and click 'View' for Billing History. Here you will be able to select a date range and access any invoices you have been issued by us.