Carbonite renews your subscription automatically, unless you go to the site and unsubscribe. It is not clear where I should do, but it seems to be in the "update payment info" link. So far, so good. I had to do that becuase they sent me an email that they will charge me an annual fee in 7 days automatically, and I am pretty sure I will try some alternative solution. And guess what I get if I try to unsubscribe?
An error occurred while processing your request.
Click back to return to the previous page and try your request again. If the problem persists, contact email@example.com.
And, if I send an email to the customer support, they say that they will reply within 72 hours!!! Fortunately I found out there is a phone number I can call, but given my experience so far, I will not be disappointed if it does not work.