Repeatables from the MailChimp template language aren't supported in Mandrill. For more details about using templates and some limitations, see the following resources:
See the note there that says: "Mandrill supports one specific element of the MailChimp template language: editable content areas (also known as mc:edit regions)."
http://kb.mailchimp.com/article/mandrill-for-mailchimp-users#templates