Go to:
cd /home/USERNAME/etc/domain.com/
Try rsync all the files under that folder to new account.
Then Copy all the mails to new account.
cp /home/USERNAME/mail/domain.com/ /home/NEW-USER/mail/
Go to:
cd /home/USERNAME/etc/domain.com/
Try rsync all the files under that folder to new account.
Then Copy all the mails to new account.
cp /home/USERNAME/mail/domain.com/ /home/NEW-USER/mail/