my $xml = <<'EOD' ;
<root>
<instance>
        <contact>
                <customerfid>101</customerfid>
                <firstname>Steve</firstname>
                <lastname>Jobs</lastname>
        </contact>
        <contact>
                <customerfid>102</customerfid>
                <firstname>mark</firstname>
                <lastname>blue</lastname>
        </contact>
</instance>
<instance>
        <contact>
                <customerfid>444</customerfid>
                <firstname>john</firstname>
                <lastname>Doe</lastname>
        </contact>
</instance>
</root>
EOD

my $data = XMLin( $xml, forcearray => ['instance', 'contact']) ;
print Dumper( $data ) ;

foreach $n (@{$data->{'instance'}}){
foreach $m (@{$data->{$n}{'contact'}}){
foreach $key (keys %{$data->{$m}}){
print "key: $key \n";
}
}
}