Mail.com on iphone 4

Today my mail.com (or post.com) stopped working on my Iphone 4.

I have seen emails about some sort of platform upgrade for a while but I have now tried setting up the account using the info in the email for hours but it doesnt work..

My phone tells me it's my imap username and password thats wrong but isn't supposed to be your email address and password?

Please I need help!