Chinese characters showing up as ?????

So everything works with Chinese characters in the website.
Except for this one plugin. bigContacts

When the Chinese characters get stored in the database,
(by inserting them into a form located in the settings page.)
they return from the database as ??????.

My database collation has been set to
utf8_unicode_ci

I have

/** 建立資料表時預設的文字編碼 */
define(‘DB_CHARSET’, ‘utf8’);

/** 資料庫對照型態。如果不確定請勿更改。 */
define(‘DB_COLLATE’, ‘utf8_unicode_ci’);

in the wp-config.

can someone tell me what the problem is?