Hey there Viki!
Can you send us a link to your site to have a look at things?
Are you by chance using the built-in editor under "Settings" -> "MailChimp Setup" or are you coding your own colors through the site's CSS?
As far as the "email format" field, that will actually have to be removed from your MailChimp list, first. You'll want to go to "Lists" -> "Settings" -> "List name and defaults". From there, you'll be able to un-check the box to allow your subscribers to choose their subscription type.
http://cl.ly/0u232H19072s3U3s0r0M
After that's unchecked, save and exit. Then, in your WordPress settings, go back to "Settings" -> "MailChimp Setup" then "Update Form Settings":
http://cl.ly/1N3f2Y3j3v1g1q1Z1N2m
Give us a shout back and we'll be happy to help!
Cheers