Returns Undefined index

gistfile1.php

$defaults = array(
	'company' 	=> 'client_company',
	'address_1' => 'client_address_1', 
	'address_2' => 'client_address_2', 
	'city' 		=> 'client_city',
	'state' 	=> 'client_state', 
	'postcode' 	=> 'client_postcode', 
	'country' 	=> 'client_country'
);

/**
 *  Parse incomming $args into an array and merge it with $defaults
 */ 
$args = wp_parse_args( $args, $defaults );

/**
 * OPTIONAL: Declare each item in $args as its own variable i.e. $type, $before.
 */ 
extract( $args, EXTR_SKIP );

//print_r( $args ); return;

$user_meta = array();

foreach ( $args as $label => $value ) {
	$user_meta[$label] .= get_user_meta( $user_id, $value, true );
}

return $user_meta;

With the $user_meta array using the $label it gives a undefined index of all the default args labels. With out the $label in the $user_meta array it's fine but outputs the count.

$user_meta[$label]:
Array
(
[company] =>
[address_1] =>
[address_2] =>
[city] =>
[state] =>
[postcode] =>
[country] =>
)

$user_meta[]:
Array
(
[0] =>
[1] =>
[2] =>
[3] =>
[4] =>
[5] =>
[6] =>
)