Hi,
This is the script your can use in RSForm in combination with Acymailing v6.
$postData = JRequest::getVar('form');
if(empty($postData['Nieuwsbrief'])) return;
include_once(rtrim(JPATH_ADMINISTRATOR,DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR.'components'.DIRECTORY_SEPARATOR.'com_acym'.DIRECTORY_SEPARATOR.'helpers'.DIRECTORY_SEPARATOR.'helper.php');
$userClass = acym_get('class.user');
$myUser = $userClass->getOneByEmail(strip_tags($postData['Email']));
if (empty($myUser)) {
$myUser = new stdClass();
}
$myUser->email = strip_tags($postData['Email']);
$myUser->name = strip_tags($postData['Name']);
$myUser->id = $userClass->save($myUser);
$listToSubscribe = [1, 2, 3];
$userClass->subscribe($myUser->id, $listToSubscribe);