International parcel stuck in Customs/Tshwane Hub

I ordered 3 parcels from China/Singapore and all entered the country in September 2017, yet I have not received any of these. One has been in the Tshwane Hub from 30/09/2017 (RF ********** 75CN), and the other 2 still reflect "Arrived at destination ZA" from 17/09/2017(RB ********** 67SG) and 30/09/2017 (RP ********** 76SG) respectively. Why are these parcels not being processed or delivered?