wordpress user metadata not saving - php

Question

I'm using the strip connect api with wordpress, and I've managed to set up the flow to connect a user, and get their access token and userid. However, I need to save this in a way that's connected to the wordpress user, as I need to be able to come back and reference the code later, in order to allow the correct person to be paid. I wrote added a couple lines with add_user_meta() but my var_dump() comes out null. here's the some of the code:
global $wpdb;
$table = $wpdb->prefix."stripe_connect";
$wpdb->insert($table , array(
'time' => current_time('mysql'),
'access_token' => $token,
'stripe_publishable_key' => $key,
'stripe_user_id' => $userid)
);
$user_ID = get_current_user_id();
add_user_meta($user_ID, ‘stripe_userid’, $userid, $unique);
add_user_meta($user_ID, ‘stripe_token’, $token, $unique);
$stripeuserid = get_user_meta($user_ID, 'stripe_userid', true);
var_dump($stripeuserid);
$response = '<h4>Thank you for connecting with Stripe. This information has been saved in the database and can be viewed in the Admin Panel.</h4>';

Answer 1

I figured it out, it had nothing to do with the way I was adding the data. The problem was with retrieving it.
This fixed it:
$user_ID = get_current_user_id();
update_user_meta($user_ID, ‘stripe_userid’, maybe_serialize( $userid ));
add_user_meta($user_ID, ‘stripe_token’, $token, $unique);
$stripeuserid = get_user_meta($user_ID, 'stripe_userid');
var_dump($stripeuserid);