One month later - parcel still missing / no answer at JIMC

I ordered a parcel from the US and it got sent to SA with DHL. It was delivered at the Johannesburg International Mail Centre on 28 July 2017, but cannot be tracked further than that delivery date - which was a month ago. I have been phoning JIMC on all of their numbers for the past two weeks and have not once managed to speak to someone there. They are always experiencing "large call volumes" and after being on hold for several minutes my call just gets dropped every time. I have no idea where my parcel is at this point and I feel like there is no way of finding out. This is very frustrating!