the option -d does not exist in userdel u should have used

userdel -r ram

now try creating the user using hacking way that is opening all the files and adding entries to the file

the file u need to edit

#/etc/passwd
#/etc/shadow
#/etc/group
#/etc/gshadow

and also create users home directory

/home/ram

and the mailbox also

#touch /var/spool/mail/ram