Made small changes in the following files.
userstat.php and detailed_stat.php

Code userstat.php row 77:
$query = 'SELECT us.*, m.name,u.name as username, m.subject, u.email, c.id as campaign_id, c.parent_id, 0 AS total_click
FROM #__acym_user_stat AS us
LEFT JOIN #__acym_user AS u ON us.user_id = u.id
INNER JOIN #__acym_mail AS m ON us.mail_id = m.id
LEFT JOIN #__acym_campaign AS c ON m.id = c.mail_id';
Added u.name as username
And in code detailed_stat.php
Row : 54 - 58
<!-- Extra toegevoegd door Marcel Snoeck / Tjooze -->
<div class="large-1 medium-1 small-1 cell acym__listing__header__title">
<?php echo acym_translation('ACYM_NAME'); ?>
</div>
<!-- -- -->
And row 110 - 114
<!-- Extra toegevoegd door Marcel Snoeck / Tjooze -->
<div class="large-1 medium-2 small-1 cell acym__listing__detailed__stats__content">
<a href="<?php echo acym_completeLink('users&task=edit&id='.$detailed_stat->user_id); ?>" class="acym__color__blue word-break"><?php echo $detailed_stat->username; ?></a>
</div>
<!-- -- -->