$VAR1 = {
  'campaign' => {
    'menuid' => '10118',
    'action' => 0,
    'phonenumbers' => [
      {
        'phonenumber' => {
          'number' => '9163723752'
        }
      },
      {
        'phonenumber' => {
          'number' => '9166413900'
        }
      }
    ]
  }
};

##</code><code>##

<campaign action="0" menuid="10118">
  <phonenumbers>
    <phonenumber number="9163723752" />
    <phonenumber number="9166413900" />
  </phonenumbers>
</campaign>

##</code><code>##

<campaign action="0" menuid="10118">
  <phonenumbers name="phonenumber" number="9163723752" />
  <phonenumbers name="phonenumber" number="9166413900" />
</campaign>

##</code><code>##

  print Dumper $xml_hash;
  my $xml_obj = XML::Simple->new( Keeproot => 1, ForceArray => 1);
  my $xmlo = $xml_obj->XMLout( $xml_hash );
  print $xmlo;