Vcard import of German Codepage Ü

Hello, I have some VCARD-contacts in german language. I am able to use them in Outlook or in Windows Contacts. Unfortunately i am not able to use them in EMClient. It seems, that EMclient doesn ́t import them in the right codepage-format. The Username is Rüdiger and it ́s imported as R?diger. Do you have any idea to help me out?