Sorry to see you go!
Before uninstalling, make sure you do not have an active paid subscription. If you do, go to Dashboard > Billing and unsubscribe.
Please know that simply uninstalling the Chrome extension will not disable your recurring charges. Recurring charges must be cancelled from the same screen you subscribed (Dashboard > Billing).
Once you confirm that no subscriptions are active, you can continue to uninstall the plugin. To uninstall: from your Chrome browser, go to the Window menu and click on Extensions (alternatively just type chrome://extensions in the address bar). This will show you the list of extensions you currently have installed. Scroll to Vocus.io and hit the trash bin icon.