Currently, Rocketspark does not offer an undo feature. however, there are a few possible ways to recover your content via external sources if the content you have deleted has been live on your site long enough for your site to be archived or cached on websites that are dedicated to keeping copies of old versions of websites.
Waybackmachine is a website that archives content from the internet. It gives you the ability to access a previously archived version of your website, allowing for content to be copied and pasted back the way it was. It can save many hours of frustration.
Please be aware, however, that your website may not have been archived so it's not always a guarantee that it will be found in the backups.
Web URL: http://archive.org/web/
CachedView is a great combination of the 3 major Web cache services out there - Google, Coral and Archive.com. You might not have the ability to roll back the years to various versions, however you have more of a chance of recovering potential recent changes to your site.
Web URL: http://cachedview.com/