Unable to purchase app gaming credits due to IMAP email password issue

What is IMAP? Recently changed email address with Apple tech support, but that remedy only lasted one day. I cannot purchase credits for gaming and refers me to a site Apple.com/support/ams/ww

[Re-Titled by Moderator]

Original Title: Email requests password for IMAP. My email password will not work. Unable to purchase credits for app gaming.