You can downgrade your individual plan to a free one and can certainly choose to not use it any more.
To downgrade an individual plan, follow these steps:
— Remove any content from your Workspace and Trash Bin.
— While logged in, go to where your username is displayed in the top right navigation, select the drop down and click on Manage Account:
— On the Resulting page, under Personal Network, click on My Personal Workspace:
— Click on the Manage Plan button, then select Basic Free plan to downgrade to:
Confirm your action by click on Downgrade button. After this point your Credit Card will not be charged.