Is Mailchimp delete-member unofficial hack?

I am trying to implement 2 mailchimp hacks – removing double optin and removing a member from s2/wordpress if they unsubscribe via mailchimp.
No luck so far:

My “/wp-content/mu-plugins/s2hacks.php” file contains only:

But the mailchimp double opt in hack isn’t working – I registered an email address on my website and it shows in users but doesn’t show up in mailchimp. (Before I added the back, registering an email would mean receiving a mailchimp double opt-in email, so it was working until then).

Should there be anything else in the hacks file? (Any essentials that I missed out?)

Also, I would like to add the hack for removing a member from the wordpress users if they unsubscribe from mailchimp.
Should my final hack file be as simple as the following?

Also, is it possible to access the hack file from directly within wordpress? I am currently going to the cpanel….

You might want to have a look at this thread where i know there is a plugin available to synchronize s2M and MC:
http://www.s2member.com/forums/topic/bidirectional-communication-s2m-mailchimp/