помогите разобраться с api смс шлюза

есть api сервиса

<?php
namespace SmsaeroApiV2;
    class SmsaeroApiV2
    {
        const URL_SMSAERO_API = 'https://gate.smsaero.ru/v2';
        private $email = 'yandex.ru'; //Ваш логин|email
        private $api_key = 'F6ebpkmkOYcIsA'; 
        private $sign = 'name'; //Подпись по умолчанию
        public function __construct($email, $api_key, $sign = false){
            $this->email = $email;
            $this->api_key = $api_key;
            if ($sign) {
                $this->sign = $sign;
            }
        }

        private function curl_post($url, array $post = NULL, array $options = array()){
            $defaults = array(
                CURLOPT_POST => 1,
                CURLOPT_HEADER => 0,
                CURLOPT_URL => $url,
                CURLOPT_FRESH_CONNECT => 1,
                CURLOPT_RETURNTRANSFER => 1,
                CURLOPT_FORBID_REUSE => 1,
                CURLOPT_TIMEOUT => 10,
                CURLOPT_POSTFIELDS => http_build_query($post),
                CURLOPT_SSL_VERIFYPEER => 0,
                CURLOPT_SSL_VERIFYHOST => 0,
                CURLOPT_USERPWD => $this->email . ":" . $this->api_key,
                CURLOPT_HTTPAUTH => CURLAUTH_BASIC,
            );
            $ch = curl_init();
            curl_setopt_array($ch, ($options + $defaults));
            if (!$result = curl_exec($ch)) {
                return curl_error($ch);
            }
            curl_close($ch);
            return $result;
        }
        public function send($number, $text, $channel, $dateSend = null, $callbackUrl = null){
            return json_decode(self::curl_post(self::URL_SMSAERO_API . '/sms/send/', [
                is_array($number) ? 'numbers' : 'number' => $number,
                'sign' => $this->sign,
                'text' => $text,
                'channel' => $channel,
                'dateSend' => $dateSend,
                'callbackUrl' => $callbackUrl
            ]), true);
        }
}
?>
<?
    $number=$_POST['number'];
$text=$_POST['text'];

$smsaero_api->send(['$number'],'$text', 'DIGITAL'); 

и форма

<div class="form-group">
                    <input type="text" class="form-control" id="number" name="number" placeholder="Введите телефон">
                </div>
            <div class="form-group">
                    <input type="text" class="form-control" id="text" name="text" placeholder="текст">
                </div>

                <button type="submit" class="btn">Отправить форму</button>
            </form>

почему не работает ?