How do i get value from wp_postmeta?

Try this :

$value = get_post_custom_values( 'banda_postmeta', $post->ID );    
$value = unserialize("$value");
print_r($value);
echo $value['social_networks_url']['twitter_url']; 

Your social_networks_url are blank, so try echoing these values, it will echo the value.

echo $value['page_builder_settings']."<br />";
echo $value['date_of_birth']."<br />";
echo $value['location']."<br />";

Output :

array (size=7)
      'social_networks_url' => 
        array (size=9)
          'twitter_url' => string 'wr' (length=2)
          'facebook_url' => string '' (length=0)
          'youtube_url' => string '' (length=0)
          'google-plus_url' => string '' (length=0)
          'linkedin_url' => string '' (length=0)
          'instagram_url' => string '' (length=0)
          'dribbble_url' => string '' (length=0)
          'github_url' => string '' (length=0)
          'pinterest_url' => string '' (length=0)
      'page_builder_settings' => string 'global' (length=6)
      'date_of_birth' => string '1932-10-24' (length=10)
      'location' => string 'California <div class="rssfeeds"><img src="http://www.speakingofbusiness.com/wp-content/uploads/2014/12/logo-rss-feed.png" width="12" /><button onclick="myFunction()">RSS</button></div>' (length=185)
      'ad' => string '<a href="http://www.kqzyfj.com/click-5434584-10365698" target="_top"> <img src="http://www.tqlkg.com/image-5434584-10365698" width="120" height="60" alt="www.1and1.com" border="0"/></a>' (length=185)
      'ad1' => string 'Hi' (length=2)
      'ad2' => string 'Hello' (length=5)




    wr
    global
    1932-10-24
    California www.1and1.com
    Hi
    Hello

See my Code and output :

    $str="a:7:{s:19:"social_networks_url";a:9:{s:11:"twitter_url";s:2:"wr";s:12:"facebook_url";s:0:"";s:11:"youtube_url";s:0:"";s:15:"google-plus_url";s:0:"";s:12:"linkedin_url";s:0:"";s:13:"instagram_url";s:0:"";s:12:"dribbble_url";s:0:"";s:10:"github_url";s:0:"";s:13:"pinterest_url";s:0:"";}s:21:"page_builder_settings";s:6:"global";s:13:"date_of_birth";s:10:"1932-10-24";s:8:"location";s:185:"California <div class="rssfeeds"><img src="http://www.speakingofbusiness.com/wp-content/uploads/2014/12/logo-rss-feed.png" width="12" /><button onclick="myFunction()">RSS</button></div>";s:2:"ad";s:185:"<a href="http://www.kqzyfj.com/click-5434584-10365698" target="_top"> <img src="http://www.tqlkg.com/image-5434584-10365698" width="120" height="60" alt="www.1and1.com" border="0"/></a>";s:3:"ad1";s:2:"Hi";s:3:"ad2";s:5:"Hello";}";
    $value = unserialize($str);

    echo $value['social_networks_url']['twitter_url']."<br />";
    echo $value['page_builder_settings']."<br />";
    echo $value['date_of_birth']."<br />";
    echo $value['location']."<br />";
    echo $value['ad']."<br />";
    echo $value['ad1']."<br />";
    echo $value['ad2']."<br />";