Solution:
you have to call them on the constructor after theĀ init_settings()
;
$this->init_settings();
// Define user set variables
$this->access_key = $this->get_option( 'access_key' );
$this->title = $this->get_option( 'title' );
$this->description = $this->get_option( 'description' );
edit:
you also need another action/hook, just at the end of the constructor, no need to create that new function that you came up with:
add_action( 'woocommerce_update_options_payment_gateways_' . $this->id, array( $this, 'process_admin_options' ) );
edit 2:
sorry you already have it, my bad :p, dont realy know what happened there, glad its solved