Here is what my developer said:
Please send them the attached screenshot and just tell them that you're trying to use their plugin and link it to your MadMimi List. You only have one list, but when you use the plugin, there's three lists in the dropdown that you can choose from: 1, 1, 7 (Not names). Also the list isn't fully displayed so you're not able to tell what list you're suppose to use.
Lastly, let them know that any of the drop down list options don't post to your Madmimi account, even with the email routed correctly to the form.
I have a screenshot I can send you to see the drop down issue. Just let me know the email address.