H1B interview appointment SHA

I am now at H1-B status. And I booked ticket to go back to Shanghai this Christmas. Since this is the first time I go back after I got the H1-B status, I have to interview with visa officer. As soon as I booked ticket, I asked my parents to make a interview appointment for me. They tried several weeks, but can never call in. Did anyone have any idea about what is happening over there? I know it usually takes hours to call in the appointment number, but taking several weeks is too ridiculous. Does anyone know any alternatives?

Thank you very much from any suggestions!