Fatal Error after MailChimp Intergration Plugin Installed

Just signed up. Installed the Dashboard. Attempted to install MailChimp Integration Plugin. It said the Directory was in use. I had previously downloaded a plugin called "MailChimp for Wordpress" and an Extension called "MailChimp Sync" (seems it was an earlier version of your code I think). So I deleted the old MC Sync plugin and selected delete all files associated with the plugin. Then from your dashboard I selected the MailChimp Integration plugin again to install. It then installed. But when I selected 'configuration' I get the following error: Fatal error: Cannot redeclare class Mailchimp_Folders in /home/content/p3pnexwpnas10_data03/79/2766879/html/wp-content/plugins/mailchimp-sync/mailchimp-api/Mailchimp/Folders.php on line 3
What do I do to fix this, please.