Q: iCloud Storage Problem

I was a mobile me user for several years and migrated to icloud months before when iCloud launched.   At the time of migration, I was taking about 2GB of storage mainly for email storage.   However, my account suspended days before due to storage overquota which is 25GB.  

I exported all mailboxes to see whether I am really consuming for such storage or not but my backup only consumes my harddisk for about 2GB only.  I really don't know how I can deal with this problem.  Is there any way to reset the account.

Attached my screen capture for reference.