PHP foreach loop doesnt itterate over objects, and won't start - php

Question

Whenever i try the following loop
if (is_object($ueberweisung)) {
print_r($ueberweisung);
foreach ($ueberweisung as $item)
{
echo '<h1>test</h1>';
echo '<tr>';
//echo '<td>' . $item['ibansender'] . '</td>';
echo '<td>' . $item->$u->getBetrag() . '</td>';
echo '<td>' . $item->u->getBicempfaenger() . '</td>';
echo '<td>' . $item->u->getBicempfaenger() . '</td>';
echo '<td>' . $item->u->getZahlungsreferenz() . '</td>';
echo '<td>' . $item->u->getVerwendungszweck() . '</td>';
echo '<td>' . $item->u->getBetrag() . '</td>';
echo '<td>' . $item->u->getDatum() . '</td>';
echo '<td>';
echo '</tr>';
}
}
it wont jump into that for each loop even though it is definitely a object and is not null$, and i don't know why.
$ueberweisung is filled by another class which is connected to a mysql database
public static function getUberweisungperIban($iban)
{
$db = Database::connect();
$sql = "SELECT * FROM ueberweisung WHERE ibansender = ?";
$stmt = $db->prepare($sql);
$stmt->execute(array($iban));
// fetch dataset (row) per ID, convert to Credentials-object (ORM)
$ueberweisung = $stmt->fetchObject('Ueberweisung');
//$ueberweisung = $stmt->fetchAll();
//return $ueberweisung;
Database::disconnect();
//return $ueberweisung;
return $ueberweisung !== false ? $ueberweisung : null;
}