How long does it take to get a parcel from overseas via OR Tambo to a Post Office near me ? .

Ordered good on the 3 May 2018 from an overseas supplier. The Tracking number is RG ********** 53CN. The goods were at OR Tambo Airport ( Post Office Sorting) on the 5 May 2018. Since then I have been phoning (011) ********** to establish its whereabouts. The latest explanation was that it was moved to WITSPOS ( part pf SA Post Office) on the 7 September 2018. The bag number at WITSPOS is RI ********** 11ZA. Seeing that after 4 months , I have still not received the parcel, the question to SA Post Offices , hoe soon can I get my parcel ? Your assistance will be greatly appreciate.