sent parcel from south africa to guangzhou in china on 28th of March still hasnt reached destination

Hi people,I need help regarding my parcel.I sent a parcel from south africa to guangzhou china on the 28th of march but has not reached the destination yet.I track the parcel almost everyday and each time i get the "NULL" message.I tracked the parcel on the 29th of May and its status was collection ,location 51051501 and destination country IT.To my amazement,a few days later the status changed to "NULL",location 51003100 and destination country IT.Please would you kindly assist explaining what is happening with my parcel.Thanks.