Obviously they made a mistake processing your application. You shouldn't have received the invitation. If I were you, I would probably write an email to the admission office to confirm the admission policy and my application status. You really don’t have panic how, since you have very little to lose.
I will locate another interviewer in Beijing to conduct your interview. The alumni interviewer will contact you directly via email to set up the date and time for the interview. Let me know if you have any questions regarding this matter.