My overseas parcel delivered to someone else!!

I ordered an International Parcel in August 2019, and followed the process of the parcel via the tracking website. All went well, until it got into the hands of the SA Post Office. My parcel was delivered to someone else!! When I asked them about it, they just tell me that I had a duplicate tracking number (!?!?!?!?!?!?!) I paid a lot of money for this parcel (in US $), and they just gave it to someone else!