Lost in transit

I purchased an item from the USA back in July 2018. According to the USPS, the package arrived in Johannesburg on the 17/07/2018 at 11:09am. It took until the 20/08/2018 to be scanned in at Johannesburg. After sitting in Customs for 2 weeks, it was released and sent down to Cape Town. According to the online tracking and the call centre, the package left Johannesburg on the 2/09/2018 - that is the last known location of the package. How does it take 51 days to travel from Johannesburg to Cape Town? Especially considering it only took 3 days to come from the other side of the world to Johannesburg.

I'm going to assume it's ****** and NEVER use the post office again!