How to insert database value into function

Hi,

I want to change the function for calculate shipping fee for woocommerce. Now the function calculate shipping from server location, But I want to change the function so it can calculate from seller location in database, not server location.
This is the function

public function init_form_fields() {
		global $woocommerce;
		global $myongkir;

		global $wpdb;

		$mylink = $wpdb->get_row( "SELECT * FROM wp_usermeta WHERE user_id='1' AND meta_key= 'billing_city'", ARRAY_A );

		if ( $this->isset_rajaongkir_api() ) {
		    $this->form_fields = array(
		    	'enabled' => array(
				    'title'   => 'Enable/Disable',
				    'type'    => 'checkbox',
				    'default' => 'no',
				    'label'   => 'Enable this shipping method',
					),
				'base_city' => array(
			        'title'       => __( 'Your Base City', 'woocommerce' ),
			        'type'        => 'select',
			        'id'          => 'woocommerce_myongkir_base_city',
			        'class'       => 'chosen_select',
			        'description' => __( 'This is your store location, used for origin package. Require api key is setted, before showing available city.', 'woocommerce' ),
			        'options'     => $myongkir->get_cities($mylink->meta_value)
			    	),
				'courier' => array(
				    'title'       => __( 'Your couriers', 'woocommerce' ),
				    'type'        => 'select',
				    'id'          => 'woocommerce_myongkir_couriers',
				    'class'       => 'chosen_select',
				    'description' => __('This is the avaibility of yours couriers', 'woocommerce' ),
				    'options' => array(
				    	'all' => 'All',
				    	'aaa' => 'aaa',
				    	'bbb' => 'bbb',
				    	'ccc'=> 'ccc',
				    ),
				),
		    );
		}
	}

I’ve found seller location in wp_usermeta table, but when I change the function base_city value to database value, the function didn’t work correctly. Do you know how I can change base_city value to database value ?

Thank you