China postal service lost parcel.

Hi! I've shipped a parcel before Chinese spring festival and it still didn't get to its destination. I've tried to track it online but there was no changes since it got to Bejing (about 2 months). Today the status changed to "NULL" . Does it mean they are going to send it back? What does this "NULL" status mean? Besides, I have two of them going through the same thing CP235434572CN and CP235434586CN.. Does anyone have any idea whats wrong?
Please could any one help me? Thanks in advance!