No Delivery/Response

I am expecting a delivery from the USA. i received notifications from UPS until my package reached South Africa on 23 June 2015. I called customer services and they told me to call customs directly as they need an invoice. I have been calling the numbers provided *** or ***. I have been trying for several days and noone 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 and what invoice is required. I have not received 1 phone call or message requesting any information. I have emailed the customer service and have not received a response. <br> <br> I cant understand why the phone lines are always busy.