Label's aren't form elements. They don't have a value. They have innerHTML and textContent.
Thus,
$('#telefon').html()
// or
$('#telefon').text()
or
var telefon = document.getElementById('telefon');
telefon.innerHTML;
If you are starting with your form element, check out the labels list of it. That is,
var el = $('#myformelement');
var label = $( el.prop('labels') );
// label.html();
// el.val();
// blah blah blah you get the idea