No response or delivery

I am expecting a delivery from Australia. I received notifications from Auspost [URL Removed] until my package reached South Africa on 16 Aug 2016. I located the parcel on Global track and trace, which states that the delivery was unsuccessful on 19 Aug 2016. No delivery attempt was made as the address is at my office. I have been calling the numbers provided *** or ***. I have been trying for several days and no one answers the phone. This is pathetic service. I am desperately trying to locate my parcel and cannot get through to speak to anyone to find out where it is . I have not received 1 phone call or message requesting any information. I have emailed the customer service and have not received a response. I am very concerned as it is an expensive item.