On the main page of your dashboard, you will find the section Upcoming Payment Schedule, which will list any upcoming payments and what company or service it is for.
For business renewal dates, select the Companies tab from the menu, then select the company name (if there is more than one). Here you find the next renewal date.
For Virtual mailboxes, select the mail tab from the menu, then select the virtual mailbox (if there is more than one). Scroll down to view the subscription information including the date created and next renewal.