Maximum limit of 10 lists

Problem:

The module retrieves only the first 10 lists from MailChimp. You can check it by calling mailchimp_get_lists function or just visit this admin page - admin/config/services/mailchimp/lists

What manual is saying?

URL: https://github.com/pacely/mailchimp-api-v3
Use offset and count in the query string to paginate data, because it provides greater control over how you view your data. Offset defaults to 0, so if you use offset=1, you'll miss the first element in the dataset. Count defaults to 10.

Solution:
Add pagination to the list or just pass the "count" parameter in mailchimp.module file on line 193:
$result = $mc_lists->getLists(array('count' => 500));