If you purchased a subscription with automatic renewal, you will be informed at least 7 days before it expires about the date of the upcoming charge and the amount you will be charged.
You can stop automatic renewals anytime by simply logging into the My Products section of your 2CO myAccount (available here) and clicking the "Stop automatic license renewal" link beneath each product with this option enabled.
To find out more about your 2CO myAccount and login instructions, click here.