MailGun获取取消订阅

Question

I am using PHP's CURL function to return all unsubscribed emails in my domain using MailGun. I tried the following code:

function get_unsubscriptions() {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
    curl_setopt($ch, CURLOPT_USERPWD, 'api:key-[key removed]');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
    curl_setopt($ch, CURLOPT_URL, 'https://api.mailgun.net/v3/[domain removed]/unsubscriptions');

    $result = curl_exec($ch);

    curl_close($ch);
    return $result;
}

But it only returns the following:

Mailgun Magnificent API

What am I doing wrong?