curl -X DELETE https://api2.ecomailapp.cz/subscribers/foo@bar.cz/delete \
  -H "key: YOUR_API_KEY" \
  -H "Content-Type: application/json"

$email = 'foo@bar.cz';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://api2.ecomailapp.cz/subscribers/{$email}/delete");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'DELETE');
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'key: YOUR_API_KEY',
    'Content-Type: application/json',
]);
$response = curl_exec($ch);
curl_close($ch);

{
  "deleted": true
}