use strict;
use  List::Compare;

my @list_one = qw/user01 user02 user03/;
my %hash_two = qw/user01 user01@emailaddress.com user03 user03@emailaddress.com user04 user04@emailaddress.com/;
my @list_two = keys %hash_two;

my $lc = List::Compare->new(\@list_one, \@list_two);

my @results = map {$_ . ' '. $hash_two{$_}} $lc->get_Ronly;

print join "\n", @results;