International parcel kept at Johannesburg International Mail Centre for longer than 3 months

I ordered something from the USA, tracking number HJ ********** 19US. According to the US company’s USPS tracking number, the parcel was processed through a facility in Johannesburg om 16/02/2018. I have not received my parcel. I did not receive any reply to my emails to EMS or the post office customer services. According to trackmyparcel, my package has been sent from Jhb, to Tshwane, to Germiston, and back to Johannesburg again. I have made numerous calls to the following phone numbers: ********** 006, ********** 007, ********** 008, each time holding for several minutes until the phone was answered, only to be put through to another department. At last I got hold of Bridget at ********** 030 on 17/04/2018. Bridget informed me that a local tracking number hadn’t been allocated to the parcel, and that she would call me back the following day. On 19/04/2018 I received an sms informing me that this parcel was either entered incorrectly, or that it has not been captured yet. Up to date nothing has been done to get my parcel to my postal address. I have spent a fortune in phone calls, and also much of my professional time in trying to get goods I paid a fortune for. What am I supposed to do now? Must I take a day off to physically go to the Johannesburg International Mail Centre? Will I even be allowed into that part of O R Tambo Airport?