diff --git a/cgi-bin/form.py b/cgi-bin/form.py
index 1b2ae7c..374d67d 100755
--- a/cgi-bin/form.py
+++ b/cgi-bin/form.py
@@ -233,7 +233,7 @@ match request_uri:
 		form_group = "CoderDojo"
 		ticket_details["Anmelde-Typ"] = get_form_value("mode")
 		ticket_details["Teilnehmenden-Name"] = get_form_value("participantname", "-")
-		ticket_details["Telefonnummer"] = get_form_value("contactphone")
+		ticket_details["Telefonnummer"] = get_form_value("contactphone", "-")
 		ticket_details["Fotos?"] = get_form_value("photos")
 
 	case _: