When an account is deactivated, you won't be able to access it, regardless of whether or not email has been received in the account during that time.
And sorry, but you can't retrieve any of the information that was formerly stored in it.
You will lose access to your Yahoo! ID, Yahoo! Mail, and profile names. yahoo will also delete your account data and settings across the Yahoo! network. This includes any contents in:
Yahoo! Mail
Yahoo! Address Book
Flickr
Yahoo! HotJobs
GeoCities
Yahoo! Briefcase
My Yahoo!
Yahoo! Groups
Finance Portfolio