So I found a solution.
I still cant get joomla to get the form values to the table so I have to do it myself by overwriting save() in my controller.
public function save()
{
$table = $this->getModel()->getTable();
$jinput = JFactory::getApplication()->input;
$JinputFilteredData = $jinput->POST->get('jform','','array');
$values = $JinputFilteredData["GroupOfFields"];
$table->bind($values);
$table->store();
return;
}
This does not seem to be the best solution though...