WPDP related functions look to work but they don’t

Formalizing comment answer here:

Based on the code you provided the problem is possibly that you are using literal strings rather than interpolated values in your SQL. There’s a big difference between backticks ` and single-quotes '.

try this:

$retArray = $wpdb->get_row("SELECT * FROM  {$wpdb->prefix}wcpl_user_packages
    WHERE DATEDIFF(NOW(), package_timestamp) >= package_dduration
      AND id = {$package->id}
      AND package_limit <> -1");

or this

$retArray = $wpdb->get_row("SELECT * FROM  {$wpdb->prefix}wcpl_user_packages
    WHERE DATEDIFF(NOW(), `package_timestamp`) >= `package_dduration`
      AND `id` = {$package->id}
      AND `package_limit` <> -1");