Face Time not working

A new U.S. sourced iPad was gifted to a German resident. Why doesn't FaceTime work in Germany? As far as I can tell all other features of the iPad work OK. The Apple Store in Hamburg, Germany suggests getting an IPhone so that the phone's sim card would work in conjunction with the iPad FaceTime feature. However this would be a significant departure from expected iPad FAceTime performance and ease of use expectations. Any suggestions? Thanks.