We know subscriptions can be annoying, and have tried to make it easy to cancel your account. Just go to Account >> Plan & Usage and then select "Change Plans" and either the "free" plan if you would like to keep access to your data, but not be charged, or "permanently delete your account," if you would like all your data and billing info wiped from our servers.
Option 1: Switch to Free
First step is to go to your account in the top right corner, rollover, and then click Plans & Usage:
On the next screen, look at the bottom of the screen below all the paid plan, and click switch to free plan.
Option 2: Permanently Delete Your Account
You can also click "permanently delete your account," right from the main page, as shown below:
This will be a permanent deletion — wiped from all backups and never to be seen again.