Connect a Deleted Mailbox to a User Account Using EAC
You can connect deleted mailboxes to user accounts using Exchange Admin Center. The process is same for all types of mailboxes – linked mailboxes, resource mailboxes and shared mailboxes.
Open EAC and go to Recipients>Mailboxes.
Click More and then select Connect a Mailbox option.
Choose a deleted mailbox from the list of disconnected mailboxes. Click Connect; click Yes. Now, you will receive a list of user accounts (not mail-enabled). Click the user account to which you want to connect the selected deleted mailbox. After that, click OK.
Now, your Exchange will connect the deleted mailbox to the selected user account, and so the deleted mailbox is available to the user again. Learn about Exchange Mailbox migration
in detail at O365CloudExperts.
I hope this manual method will be useful to recover deleted Exchange mails.