To contact your producer, log into your account and go to the page where you need changes.
For ads, click the green Build My Ads button, for videos click the red Manage My Video button, and for website click the purple Manage my Website. Once on the correct page, click the Add Comment or File button and leave a comment. The comment automates an email that is sent to your producer. Your producer will respond the same way, and an automated email will be sent to you letting you know a comment has been left for you.
Keep in mind that direct response to the automated emails will not be sent to the producer.